feat(stage): add tab session action menu

[ovdmar]

Summary

• Move per-tab reload and close-tab controls into an inline tab actions menu.
• Add a reload-session action that resumes the tab's agent runtime session in place, preserving the stable tab id and keeping the tab visible while the runtime relaunches.
• Add backend and frontend coverage for reload routing, runtime resume gating, tab order preservation, pending reload rendering, and menu behavior.

Plan

Inline / trivial

Test plan

• make check passes locally
• pnpm e2e:isolated passes locally
• pnpm smoke passes (not run)
• Manual QA per the How-to-QA section below

How to QA

1. Pull the branch: git checkout mighty-weasel
2. Install: pnpm install
3. Full check: make check
4. Start the daemon + web in dev mode: pnpm dev
   • Daemon: http://localhost:4010
   • Web cockpit: http://localhost:5173
5. Open a workspace with live session tabs and confirm each tab has a compact actions menu instead of separate reload/close icons.
6. For an agent tab with a persisted runtime session id and a resumable runtime, choose Reload session and confirm the tab stays visible, remains in the same position, and resumes into the replacement session.
7. Confirm non-agent tabs do not show Reload session, non-resumable agent runtimes show it disabled, and the close action is labeled Close tab.

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