fix(vscode): prevent completed sessions from staying busy

[marius-kilocode]

What Problem This Solves

Completed Agent Manager and sidebar sessions can remain stuck on "Considering next steps" even after the backend has finished and the final assistant response is persisted. Pressing Stop can make a normally completed session appear interrupted.

Why This Change Was Made

Live SSE events and directory-wide HTTP status snapshots update the same session state independently. A delayed snapshot can overwrite a newer idle event, overlapping snapshots can arrive out of order, and reconnects previously avoided reconciling already-known busy sessions.

Track session event freshness and directory request ordering, reconcile sessions omitted from authoritative status responses, and recheck status after terminal assistant or turn-close events. Preserve worktree directory boundaries and the explicit-abort handling already present on main.

User Impact

Completed sessions return to the idle state, the working indicator disappears, and the Send control becomes available again. Active sessions and sessions in other worktrees are not incorrectly marked idle.

Evidence

• bun run build:check passes, including extension typecheck, webview typecheck, lint, and bundling.
• bun run test:unit: 4,194 tests passed.
• bun run knip and bun run check-kilocode-change pass.
• Six focused regression cases cover stale busy responses, missing idle recovery, overlapping directory and seed requests, and worktree isolation.
• Isolated VS Code Agent Manager verification confirmed a completed local test-model session returns to idle without a stuck indicator or interruption warning.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (4 files)

• .changeset/fix-stale-agent-session-status.md
• packages/kilo-vscode/src/KiloProvider.ts
• packages/kilo-vscode/src/session-status.ts
• packages/kilo-vscode/tests/unit/kilo-provider-load-messages.test.ts

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_{Reviewed by grok-4.6 · Input: 128.8K · Output: 29.6K · Cached: 2.5M}

_{Review guidance: REVIEW.md from base branch main}