fix(mobile): keep the one-shot Ctrl armed through terminal-generated reports

Review of #268 turned up two defects, both verified against a real shell
session on an isolated instance.

1. A tap spent the modifier. The onData hook consumed every chunk while
   armed, but not every chunk is a keystroke: a shell session keeps the
   narrow scrollback strip, so mouse DECSETs reach the browser, and with
   vim/htop running a tap arrives as `\x1b[<0;31;23M`. Measured in the
   real app: armed, one tap, disarmed, and the Ctrl button read as dead.
   The hook now skips mouse and focus reports via a new
   `CodemanTerminalInput.isTerminalFocusOrMouseReport()`; they still reach
   the PTY, they just no longer stand in for the next key. Focus reports
   are covered for the same reason even though FOCUS_ESCAPE_FILTER in
   session.ts strips DECSET 1004 today, since the bar refocuses the
   terminal after every key and would spend the modifier on its own
   `\x1b[I` the moment that filter changed.

2. The armed style did not land on the four light skins. The competing
   rule is (0,3,1), not (0,2,1) as the comments claimed: `:is()` takes the
   specificity of its most specific argument and that list holds
   `.btn-toolbar.btn-shell`, so it outranked the (0,3,0) armed rules in
   both stylesheets. Measured across all seven skins at 390px, armed and
   resting backgrounds were byte-identical on paper-gray, solarized-light,
   catppuccin-latte and rose-pine-dawn. The light-skin rule now excludes
   the state as `.accessory-btn:not(.armed)`, which fixes phone and tablet
   at once; adding another class to the armed rules would only have moved
   the tie.

Tests: 20 more cases in test/mobile-shell-keyboard.test.ts (the report
classifier, the gate's effect on the modifier, and a static guard on the
light-skin selector, since the existing E2E background assertion passes on
a light skin and the browser suite runs the dark default), plus a browser
regression that taps the terminal with mouse reporting on.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -270,7 +270,7 @@ Frontend JS modules have `@fileoverview` with `@dependency`/`@loadorder` tags. L
 
 **WebGL renderer toggle** (`webglRendererEnabled`, per-device): the GPU-stall watchdog's sticky `codeman-webgl-disabled` marker survives page loads and is cleared only by an explicit OFF→ON save or `?webgl=force`. `?nowebgl` forces the DOM renderer per-load. → [architecture-invariants#webgl-renderer-toggle](docs/architecture-invariants.md#webgl-renderer-toggle)
 
-**Shell keyboard accessory bar + one-shot Ctrl** (issue #262, `keyboard-accessory.js`): a **shell**-mode session automatically swaps the mobile accessory bar for terminal controls (Ctrl, Esc, Tab, four arrows, paste, dismiss); every other mode keeps the agent bar. `setMode()` now records the user's `extendedKeyboardBar` preference as the **base** layout and `refreshForActiveSession()` (called from `selectSession`) resolves base-vs-shell, so a settings save during a shell session cannot yank the bar away and switching back restores the user's choice. ⚠️ **Ctrl is a ONE-SHOT modifier applied in `terminal.onData`, not in a keydown handler**: a virtual keyboard emits no usable key events, so the character only exists as onData text. The hook sits AFTER `shouldSuppressTerminalQueryResponse` (xterm answers DA/CPR through onData too, and one of those would silently spend the modifier) and BEFORE every send path, so the control byte follows the normal control-char route. ⚠️ It must disarm on ALL of: use, second tap, any other accessory key, session switch, keyboard dismissal, and a layout swap; a modifier left armed turns the next innocent keystroke into a control byte. Mapping is `ctrlByteFor()` (`code & 0x1f` over @A-Z[\]^_ and a-z, plus Ctrl+Space=NUL / Ctrl+?=DEL); characters with no control equivalent pass through unchanged, like a hardware keyboard. The armed style needs **three classes** (`.accessory-btn.accessory-btn-ctrl.armed`) to outrank mobile.css's light-skin `.accessory-btn` rule at (0,2,1).
+**Shell keyboard accessory bar + one-shot Ctrl** (issue #262, `keyboard-accessory.js`): a **shell**-mode session automatically swaps the mobile accessory bar for terminal controls (Ctrl, Esc, Tab, four arrows, paste, dismiss); every other mode keeps the agent bar. `setMode()` now records the user's `extendedKeyboardBar` preference as the **base** layout and `refreshForActiveSession()` (called from `selectSession`) resolves base-vs-shell, so a settings save during a shell session cannot yank the bar away and switching back restores the user's choice. ⚠️ **Ctrl is a ONE-SHOT modifier applied in `terminal.onData`, not in a keydown handler**: a virtual keyboard emits no usable key events, so the character only exists as onData text. The hook sits AFTER `shouldSuppressTerminalQueryResponse` (xterm answers DA/CPR through onData too, and one of those would silently spend the modifier) and BEFORE every send path, so the control byte follows the normal control-char route. ⚠️ **Not every onData chunk is a keystroke**, and the query filter is not enough on its own: xterm ALSO emits mouse and focus reports on its own initiative, so the hook skips them via `isTerminalFocusOrMouseReport()` (they still reach the PTY, they just don't count as the next key). The mouse half is live — a shell session keeps the NARROW strip, so mouse DECSETs reach the browser and one tap while vim/htop runs spent the armed modifier silently (measured). The focus half is defense in depth: `FOCUS_ESCAPE_FILTER` in `session.ts` strips `\x1b[?1004h` from every PTY read, so `sendFocusMode` never turns on today; if it ever did, the bar's own post-key refocus would emit `\x1b[I` and eat the modifier before the user typed. ⚠️ It must disarm on ALL of: use, second tap, any other accessory key, session switch, keyboard dismissal, and a layout swap; a modifier left armed turns the next innocent keystroke into a control byte. Mapping is `ctrlByteFor()` (`code & 0x1f` over @A-Z[\]^_ and a-z, plus Ctrl+Space=NUL / Ctrl+?=DEL); characters with no control equivalent pass through unchanged, like a hardware keyboard. ⚠️ The armed style is `.accessory-btn.accessory-btn-ctrl.armed` (0,3,0) in BOTH stylesheets, and it cannot outrank mobile.css's light-skin repaint at **(0,3,1)** (`:is()` inherits its most specific argument, and that list holds `.btn-toolbar.btn-shell`) — so that rule excludes the state by hand as `.accessory-btn:not(.armed)`. Without the exclusion the armed button renders identically to a resting one on all four light skins, which is worse than no armed style at all.
 
 **Phone toolbar: Enter replaces Shell** (post-1.8.0): inside `@media (max-width: 430px)` `btn-shell` is `display:none` and `btn-enter` takes its slot (`order: 4`); starting a shell moved into the Run dropdown (`Terminal / Shell` → `setRunMode('shell')` → `run()` → `runShell()`, button label "Run SH"). `runMode` is `z.string().max(20)` server-side, so new modes need no schema change. Desktop and tablet keep the green Run Shell button unchanged.