Give the mouse back, retire the follow controls, update Claude per session

Three things the terminal was getting wrong.

**A program that grabs the mouse and dies used to freeze the tab.** A TUI sets
DECSET ?1000/?1002/?1003; if it exits without resetting them, xterm keeps
routing clicks, drags and — under ?1003 — every pointer *move* to the PTY.
Text selection dies and escape bytes flood the prompt. The only exit was
closing the tab. `TerminalView` now reconciles a flag against
`term.modes.mouseTrackingMode` in the `term.write()` callback — the mode only
changes because the container printed a sequence, so one check per write
catches every transition with no polling — and `Ctrl+Shift+X` or a status-bar
button writes the resets back through `term.write`, never `sendInput`: the
reset belongs to xterm's parser, and a still-live TUI told about it would just
re-grab on its next repaint.

The control is in the status bar deliberately. Mouse tracking is the *normal*
state of htop, vim, lazygit and Claude Code, so a badge over the terminal
would be on screen for the whole life of those programs and would swallow
clicks aimed at their own top-right corner. `macOptionClickForcesSelection` is
also on now: xterm's force-select is Shift everywhere except macOS, where it
is Option and is gated behind that option, which defaults to false — so until
now Mac users had no way to select text while a program held the mouse.

**"Following" and "Jump to Current" are gone.** Claude Code draws on the
alternate screen, which has no scrollback, so `viewportY` always equalled
`baseY` and neither control could do anything. They did still work in bash
tabs; xterm's native follow covers that, and the per-write `scrollToBottom()`
went with them because it fought exactly that. What remains, on activate and
after a refit, now samples `viewportY >= baseY` *before* the fit, so opening
the Notes dock no longer yanks a reader to the tail.

**`claude update` runs before every Claude session, not just at container
start.** Containers here stop/start and often just keep running, so a
long-lived one never re-checked. Both copies take the same flock: the
entrypoint prints "container ready" only after its own update finishes, so
opening a tab immediately would otherwise run two updaters against the same
~/.claude/bin, with `|| echo` hiding a half-written install one line before
`exec claude` ran it.

This turns the non-Bedrock path from a bare argv into a `bash -c` wrapper, so
flags and session names are shell-interpolated now and must go through
`shell_quote_arg`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0145mQi9NZiCDrznBUEEDE4n

container/entrypoint.sh

@@ -639,8 +639,14 @@ fi
 # any terminal session launches `claude`. Runs as the claude user (the CLI is
 # installed under /home/claude/.claude/bin). Non-fatal and time-bounded so a
 # slow or offline network never blocks container readiness.
+# The lock is shared with the per-session update that every Claude terminal
+# runs before `exec claude` (commands/terminal_commands.rs, UPDATE_PRELUDE).
+# "Container ready" is printed *after* this finishes, so a user who starts a
+# project and immediately opens a tab would otherwise have two updaters
+# rewriting ~/.claude/bin at once, and the session's `|| echo` would hide the
+# damage right before it ran the result.
 echo "entrypoint: checking for Claude Code updates..."
-timeout 120 su -s /bin/bash claude -c 'export PATH="/home/claude/.claude/bin:/home/claude/.local/bin:$PATH"; claude update' \
+timeout 120 su -s /bin/bash claude -c 'export PATH="/home/claude/.claude/bin:/home/claude/.local/bin:$PATH"; flock -w 90 -E 0 /tmp/.triple-c-claude-update.lock claude update' \
     && echo "entrypoint: Claude Code is up to date" \
     || echo "entrypoint: warning — Claude Code update skipped or failed (continuing)"