refactor(web): remove the agents right panel

[maria-rcks]

The thread's lineage control already shows its subagents, so the duplicate Agents right-panel surface is removed. This deletes the tab, launcher/menu entry and shortcut, roster, and panel-toggle badge; the badge existed only to point at that surface. The elapsed helper moves unchanged beside lineage, and persisted Agents selections fall back to a surviving tab or close an empty panel.

Verified on Blacksmith: web typecheck, targeted lint (0 errors), and all 92 tests across the two affected existing test files. Browser checks with a real-data snapshot covered Files/Diff switching, the add menu, lineage expansion and child navigation, and legacy persisted state migration (including preserving a closed panel's surviving selection). No new test files.

All required checks pass on 71820f35433c5a2eed87db5467c6acd89dd7faa4, including all server shards. Two independent final code reviews approved this head.

Known follow-up: lineage excludes native subagents without a child thread. This pass follows the explicit request to delete the roster and leave lineage unchanged; transcript subagent rendering is preserved.

Before, dark:

Before, light:

After, dark:

After, light:

Written by gpt-6-astra (Codex) in T3 Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This change removes the dedicated Agents right-panel workflow, including its roster, workflow/script details, token summaries, shortcut, and live-status affordances, while migrating persisted panel state to the remaining surfaces. The replacement lineage display and cleanup are coherent, but the user-facing behavior change is substantial enough to require human review.

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