feat(v0.11): Stuck Session Alerts — detect and surface session.stuck events in real time

[vivekchand]

Problem

From the same real-world deployment:

"There were stretches where I had no idea if it was making progress, stuck in a loop, or waiting on a hanging install process."

OpenClaw emits session.stuck diagnostic events when a session exceeds expected duration. ClawMetry receives these via the log stream but does nothing with them.

What's Already There

• /api/logs-stream SSE tails the log file (issue feat(v0.11): Live Log Tail Tab — real-time /tmp/openclaw/*.log viewer with filtering #27)
• OTLP receiver already handles openclaw.session.stuck metric
• startLogStream() already processes every log line in JS

What's Missing

When a session.stuck event appears in the log stream:

1. Top banner — persistent alert with session key, stuck duration, link to transcript. Appears on every tab. Dismissable.
2. Sessions tab badge — count of currently stuck sessions
3. Red highlight on stuck session rows

Alert clears automatically when a terminal session.state event arrives for that session.

Where to Change

1. Add banner HTML — one <div id="stuck-banner"> just after the nav bar closes, before the first <div class="page"> block.

2. In startLogStream() JS (line 5202, logStream.onmessage) — add a check: if the parsed line contains session.stuck, call showStuckAlert(sessionId, ageMs).

3. Add showStuckAlert() function — updates the banner, increments a badge on the Sessions nav tab.

4. Clear on terminal state — same onmessage handler: if line contains session.state with a terminal value, call clearStuckAlert(sessionId).