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/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.