fix(terminal): merge-time fixes for #498

- _logScrollRouting() reports cliMouseTracking, the gate's new input, in both
  the de-dup signature and the console line (xterm's own mouseTracking stays
  'none' for Claude, so it gave no reason for a no).
- Restore two guard tests the new gate made vacuous: the local-scrollback
  opt-out footgun test and the codex/gemini "no version rescues it" fixtures
  now set cliMouseTracking: true, so removing the opt-out or re-adding codex to
  the gate fails again.
- Update the comments and architecture-invariants lines that still described
  the version-only rule (wheel handler header, gate doc, the false paths of
  _maybePageCliTranscript, "holds a tracking mode on continuously").
- Name both fullscreen switches (CLAUDE_CODE_NO_FLICKER=1 and "tui":
  "fullscreen" in ~/.claude/settings.json) in the code comment, the invariants
  and the two wiki pages.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -215,13 +215,13 @@ Further detail: the `<prefix>: <title>` form (`w3-myapp: fix the login redirect`
 
 **Two strip flavors, one carry** (#205, `session.ts:_handleTerminalOutput`): the FULL strip (`isAltScreenStripMode` = codex/claude/gemini) removes alt-screen toggles, `3J`, and mouse-tracking DECSETs. Every other mode (shell/opencode/antigravity/pi) gets the NARROW strip (`isMuxAltScreenOnlyStripMode`) — alt-screen toggles ONLY — and only when tmux-backed (`useMux`). Rationale: the tmux CLIENT emits `smcup` as its first bytes at attach, before any program runs, parking xterm in the scrollback-less alternate buffer for the whole session (touch scrolling no-ops; xterm's own wheel handler converts the wheel to Up/Down arrows = readline history cycling — both #205 symptoms). tmux never forwards a pane program's alt-screen toggles to its client (it repaints instead; measured — vim/less inside a pane emit zero to the client), so the only thing the narrow strip ever removes is tmux's own smcup. It keeps `3J` (a user's `clear` is a deliberate scrollback wipe) and the mouse DECSETs (tmux passes those through even with `mouse off`; stripping them would break htop/vim mouse support). ⚠️ The `useMux` gate is load-bearing: `startShell()`/`startInteractive()` fall back to a DIRECT PTY when mux creation fails, and there the inner program's own `?1049h` really does reach xterm — stripping it would break vim/less/htop for real. The replay path (`session-routes.ts`, via `session.usesMux`) applies the same narrow branch; the frontend mirror (`_shouldReportMouseToCli()`) stays claude/codex/gemini because only the FULL strip touches mouse DECSETs. The chunk-boundary carry (`_altScreenSeqCarry`) runs for both flavors. Tests: `test/claude-scrollback-strip.test.ts`.
 
-⚠️ **What the full strip removes, it must REMEMBER.** Stripping the mouse DECSETs means xterm's `modes.mouseTrackingMode` is permanently `'none'` for those modes, so the browser hand-encodes click reports to compensate (`_sendSyntheticSgrTap`). With no state to consult it did that on EVERY click, which delivered mouse reports to programs that never asked for them: the same pane runs a plain shell whenever the CLI has exited or a `shell` was started inside a claude-mode session, and a shell prints the report as literal text (`[<0;88;20M`), garbling the next line typed. `_recordStrippedMouseMode()` therefore records each stripped sequence as it goes and publishes `cliMouseTracking` through `toState()`, and `_shouldReportMouseToCli()` requires it. ⚠️ Only the TRACKING modes count (1000/1001/1002/1003): 1005/1006 select an ENCODING and 1007 is alt-scroll, and counting those would put the stray reports straight back. ⚠️ The change broadcasts IMMEDIATELY rather than through `broadcastSessionStateDebounced`, because the flag flips when a dialog opens and the user can click that dialog inside the 500ms debounce window. Measured on a live claude 2.x: the CLI holds a tracking mode on continuously (so clicks keep being reported exactly as before), while a bash prompt in the same stripped mode reports nothing. Fails toward silence: after a server restart the flag is false until the CLI re-emits, which tmux does at client attach.
+⚠️ **What the full strip removes, it must REMEMBER.** Stripping the mouse DECSETs means xterm's `modes.mouseTrackingMode` is permanently `'none'` for those modes, so the browser hand-encodes click reports to compensate (`_sendSyntheticSgrTap`). With no state to consult it did that on EVERY click, which delivered mouse reports to programs that never asked for them: the same pane runs a plain shell whenever the CLI has exited or a `shell` was started inside a claude-mode session, and a shell prints the report as literal text (`[<0;88;20M`), garbling the next line typed. `_recordStrippedMouseMode()` therefore records each stripped sequence as it goes and publishes `cliMouseTracking` through `toState()`, and `_shouldReportMouseToCli()` requires it. ⚠️ Only the TRACKING modes count (1000/1001/1002/1003): 1005/1006 select an ENCODING and 1007 is alt-scroll, and counting those would put the stray reports straight back. ⚠️ The change broadcasts IMMEDIATELY rather than through `broadcastSessionStateDebounced`, because the flag flips when a dialog opens and the user can click that dialog inside the 500ms debounce window. Measured on a live claude 2.x: the CLI holds a tracking mode on continuously in fullscreen (so clicks keep being reported exactly as before; the default inline renderer holds none, measured on 2.1.283 even with `/model` open), while a bash prompt in the same stripped mode reports nothing. Fails toward silence: after a server restart the flag is false until the CLI re-emits, which tmux does at client attach.
 
-**Only claude ≥ 2.1.187 with mouse tracking on forwards the wheel; everything else scrolls local scrollback** (#227 follow-up, `terminal-ui.js:_shouldForwardWheelToApp`). Codex was in the forward list until a reporter hit a completely dead wheel in codex tabs while the scrollbar drag worked. Measured against codex-cli 0.147.0 in a bare tmux: it never enables mouse tracking (`mouse_any_flag=0`) and SGR wheel reports fed to its PTY change nothing on screen, because it runs an INLINE viewport (`alternate_on=0`) and pushes its transcript into the terminal's own scrollback (tmux `history_size` grows) instead of paging in-app. So for codex, local scrollback IS the transcript and forwarding swallowed every tick. Claude repeats this exactly in its default INLINE renderer (measured on 2.1.280: `alternate_on=0`, `mouse_any_flag=0`, `history_size` grows), and swipes on iOS Safari were dead there while codex scrolled; only fullscreen claude (`CLAUDE_CODE_NO_FLICKER=1`: alt screen plus modes 1003/1006) pages its transcript on wheel reports. So claude forwards only while the server-observed `cliMouseTracking` flag is true; a stale-false flag after a server restart falls through to the PageUp/PageDown fallback, never a dead wheel. ⚠️ "The TUI is a strip mode" is NOT evidence that it consumes wheel reports — verify with a real `\x1b[<64;c;rM` write into a live pane before adding a mode here. Hand-encoded SGR TAPS are gated by `_shouldReportMouseToCli()` (strip mode AND the server-observed `cliMouseTracking` flag, recorded by `_recordStrippedMouseMode` in session.ts as it strips): codex never enables mouse tracking, so since #325 no tap report is sent there at all — click-to-position was already a measured no-op in codex, and a pane that has fallen back to a shell no longer receives `[<0;88;20M` junk.
+**Only claude ≥ 2.1.187 with mouse tracking on forwards the wheel; everything else scrolls local scrollback** (#227 follow-up, `terminal-ui.js:_shouldForwardWheelToApp`). Codex was in the forward list until a reporter hit a completely dead wheel in codex tabs while the scrollbar drag worked. Measured against codex-cli 0.147.0 in a bare tmux: it never enables mouse tracking (`mouse_any_flag=0`) and SGR wheel reports fed to its PTY change nothing on screen, because it runs an INLINE viewport (`alternate_on=0`) and pushes its transcript into the terminal's own scrollback (tmux `history_size` grows) instead of paging in-app. So for codex, local scrollback IS the transcript and forwarding swallowed every tick. Claude repeats this exactly in its default INLINE renderer (measured on 2.1.280: `alternate_on=0`, `mouse_any_flag=0`, `history_size` grows), and swipes on iOS Safari were dead there while codex scrolled; only fullscreen claude (`CLAUDE_CODE_NO_FLICKER=1` or `"tui": "fullscreen"` in `~/.claude/settings.json`: alt screen plus modes 1003/1006) pages its transcript on wheel reports. So claude forwards only while the server-observed `cliMouseTracking` flag is true; a stale-false flag after a server restart falls through to the PageUp/PageDown fallback, never a dead wheel. ⚠️ "The TUI is a strip mode" is NOT evidence that it consumes wheel reports — verify with a real `\x1b[<64;c;rM` write into a live pane before adding a mode here. Hand-encoded SGR TAPS are gated by `_shouldReportMouseToCli()` (strip mode AND the server-observed `cliMouseTracking` flag, recorded by `_recordStrippedMouseMode` in session.ts as it strips): codex never enables mouse tracking, so since #325 no tap report is sent there at all — click-to-position was already a measured no-op in codex, and a pane that has fallen back to a shell no longer receives `[<0;88;20M` junk.
 
-**Wheel/touch forwarding is NOT gated on viewport-at-bottom** (#205, `terminal-ui.js:_shouldForwardWheelToApp`): for sessions verified to scroll their own transcript on SGR wheel reports (claude ≥ 2.1.187 — version via the local/docker/remote `--version` probes), the plain wheel AND touch drags forward as coalesced SGR reports (`_forwardScrollToApp` → `_sendSyntheticSgrWheel`, 40ms batches, 5-tick cap, 512-byte queue bound). It used to gate on the viewport being at the bottom so both scrollbacks stayed reachable, but a repaint-mode CLI keeps NO terminal scrollback of its own — xterm's buffer holds only replayed repaint frames, so local scrolling drags the CLI's pinned prompt box up the screen over stale frames; and `scrollToLastNonEmptyLine()` routinely parked the viewport off-bottom, silently pinning the wheel to local. Forwarding now snaps the viewport home first (SGR coordinates address the LIVE screen — a report computed from a scrolled-up viewport would hit-test the wrong row). Local scrollback remains on Shift+wheel and the `terminalWheelLocalScrollback` opt-out (both also cover touch via the shared gate; touch has no Shift, so the setting is its only local pin). `_wheelScrollLines()` normalizes `deltaMode` (Firefox fires LINE deltas ≈3/notch — read as pixels that rounded to 0 and fell to the ±1 fallback, ~4× too slow; PAGE deltas scale by `terminal.rows`) while keeping the #154 Shift-axis trap (macOS trackpads put Shift+scroll magnitude on deltaX). Tests: `test/terminal-touch-tap.test.ts`.
+**Wheel/touch forwarding is NOT gated on viewport-at-bottom** (#205, `terminal-ui.js:_shouldForwardWheelToApp`): for sessions verified to scroll their own transcript on SGR wheel reports (claude ≥ 2.1.187 while `cliMouseTracking` is true, i.e. fullscreen; version via the local/docker/remote `--version` probes), the plain wheel AND touch drags forward as coalesced SGR reports (`_forwardScrollToApp` → `_sendSyntheticSgrWheel`, 40ms batches, 5-tick cap, 512-byte queue bound). It used to gate on the viewport being at the bottom so both scrollbacks stayed reachable, but a repaint-mode CLI keeps NO terminal scrollback of its own — xterm's buffer holds only replayed repaint frames, so local scrolling drags the CLI's pinned prompt box up the screen over stale frames; and `scrollToLastNonEmptyLine()` routinely parked the viewport off-bottom, silently pinning the wheel to local. Forwarding now snaps the viewport home first (SGR coordinates address the LIVE screen — a report computed from a scrolled-up viewport would hit-test the wrong row). Local scrollback remains on Shift+wheel and the `terminalWheelLocalScrollback` opt-out (both also cover touch via the shared gate; touch has no Shift, so the setting is its only local pin). `_wheelScrollLines()` normalizes `deltaMode` (Firefox fires LINE deltas ≈3/notch — read as pixels that rounded to 0 and fell to the ±1 fallback, ~4× too slow; PAGE deltas scale by `terminal.rows`) while keeping the #154 Shift-axis trap (macOS trackpads put Shift+scroll magnitude on deltaX). Tests: `test/terminal-touch-tap.test.ts`.
 
-**A false gate on a Claude session must not mean a DEAD gesture** (#205 round 2, `_maybePageCliTranscript`): every way `_shouldForwardWheelToApp()` returns false leaves a repaint-mode pane scrolling a buffer that has nothing in it (`baseY === 0`) — the version probe came back empty, the CLI really is older than 2.1.187, or the user turned on `terminalWheelLocalScrollback`. The 1.12.0 retest reported exactly that: a wheel that did nothing at all while Fn+Up (PageUp) paged back through intact text, which is the proof that the CLI's own history and the PTY input path were both fine. So under the triple guard (claude mode + gate false + `baseY === 0`) wheel and touch travel is translated into coalesced `\x1b[5~` / `\x1b[6~` through the same 40ms queue as the SGR reports, at half a screen of travel per page key (the key jumps a whole screen; a 1:1 mapping was unusably slow with a discrete wheel). ⚠️ Shift is excluded on purpose — it is the explicit "give me local scrollback" gesture and must keep that meaning. ⚠️ `terminalWheelLocalScrollback` is deliberately NOT scoped away from repaint-mode CLIs even though it is a footgun there: that would silently override an explicit user choice, so the fallback catches it instead. **Server-side counterpart**: `getClaudeCliVersion()` caches SUCCESS for the process lifetime but must never cache FAILURE — it used to, so one timed-out or PATH-starved probe at the first Claude session start disabled wheel-forwarding for every Claude session until the server restarted (a dead wheel on phone, tablet and laptop at once, the signature of a server-side cause). Failures now retry with a 1/2/4…15min backoff; the policy is the pure `resolveClaudeCliVersion()`. Tests: `test/terminal-scroll-routing.test.ts`, `test/claude-cli-version-cache.test.ts`.
+**A false gate on a Claude session must not mean a DEAD gesture** (#205 round 2, `_maybePageCliTranscript`): every way `_shouldForwardWheelToApp()` returns false leaves a repaint-mode pane scrolling a buffer that has nothing in it (`baseY === 0`) — the version probe came back empty, the CLI really is older than 2.1.187, the `cliMouseTracking` flag is unset (inline claude, or fullscreen right after a server restart), or the user turned on `terminalWheelLocalScrollback`. The 1.12.0 retest reported exactly that: a wheel that did nothing at all while Fn+Up (PageUp) paged back through intact text, which is the proof that the CLI's own history and the PTY input path were both fine. So under the triple guard (claude mode + gate false + `baseY === 0`) wheel and touch travel is translated into coalesced `\x1b[5~` / `\x1b[6~` through the same 40ms queue as the SGR reports, at half a screen of travel per page key (the key jumps a whole screen; a 1:1 mapping was unusably slow with a discrete wheel). ⚠️ Shift is excluded on purpose — it is the explicit "give me local scrollback" gesture and must keep that meaning. ⚠️ `terminalWheelLocalScrollback` is deliberately NOT scoped away from repaint-mode CLIs even though it is a footgun there: that would silently override an explicit user choice, so the fallback catches it instead. **Server-side counterpart**: `getClaudeCliVersion()` caches SUCCESS for the process lifetime but must never cache FAILURE — it used to, so one timed-out or PATH-starved probe at the first Claude session start disabled wheel-forwarding for every Claude session until the server restarted (a dead wheel on phone, tablet and laptop at once, the signature of a server-side cause). Failures now retry with a 1/2/4…15min backoff; the policy is the pure `resolveClaudeCliVersion()`. Tests: `test/terminal-scroll-routing.test.ts`, `test/claude-cli-version-cache.test.ts`.
 
 **Why the wheel went where it went is LOGGED** (`_logScrollRouting`): one console line per session per distinct decision — `[scroll] <id> → forward-sgr|page-keys|local-scrollback|repull-refused-downgrade (mode=…, cliVersion=…, localScrollbackOptOut=…, mouseTracking=…, localScrollbackRows=…)`. #205 ran two rounds of remote guesswork over questions this line answers directly; keep it when touching the routing.
 

docs/wiki/The-Dashboard.md

@@ -155,7 +155,8 @@ Worth knowing:
   history; press **Load full history** to pull the rest explicitly. Automatic output
   recovery stays within the bounded browser buffer.
 - **Wheel and touch scrolling** are forwarded into Claude's own transcript when a recent
-  Claude runs fullscreen, so the wheel scrolls the conversation rather than the terminal.
+  Claude runs fullscreen (`CLAUDE_CODE_NO_FLICKER=1`, or `"tui": "fullscreen"` in
+  `~/.claude/settings.json`), so the wheel scrolls the conversation rather than the terminal.
   Claude's default inline view keeps its history in the terminal and scrolls locally. `Shift+Wheel` is
   always local scrollback. Other CLIs scroll locally.
 - **Selection copy.** `Ctrl+C` copies when text is selected and interrupts when it is not.

docs/wiki/Troubleshooting.md

@@ -166,7 +166,9 @@ Things to try:
 - `Shift+Wheel` always scrolls the local buffer, whatever else is going on.
 - On Claude sessions running fullscreen (recent CLI with mouse tracking on), the wheel is
   forwarded into Claude's own transcript, so it scrolls the conversation rather than the
-  terminal buffer. That is intended. Claude's default inline view scrolls locally.
+  terminal buffer. That is intended. Claude's default inline view scrolls locally; turn
+  fullscreen on with `CLAUDE_CODE_NO_FLICKER=1` or `"tui": "fullscreen"` in
+  `~/.claude/settings.json`.
 - Scrolling to the very top pulls the full tmux scrollback again on demand.
 
 ### The wheel does nothing in a Codex session