Sync upstream through 14f15cfed

[aaditagrawal]

Summary

• merge the latest four upstream commits through 14f15cfed
• preserve the fork-only sidebar artwork preference while adding the opt-in context-window meter
• keep the new lightweight linked-PR summary RPC backward-compatible with older connected servers via an advertised capability and detail fallback

Verification

• node_modules/.bin/vp check (0 errors; 41 existing warnings)
• node_modules/.bin/vp run typecheck
• focused affected suites: 353 upstream tests plus 16 capability/fallback tests
• full workspace: 987 files passed / 3 skipped; 10,730 tests passed / 26 skipped
• integrated web: context-window indicator defaults off, toggles on, and persists after reload
• three independent review lanes clean after the version-skew fix

Upstream interaction was fetch-only; this PR targets aaditagrawal/t3code:main.

[aaditagrawal]

• Sync upstream through 14f15cfed #261 👈 (View in Graphite)
• main

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.2 KiB	13.2 KiB	−1 B (−0.0%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+1 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.3 KiB	6.3 KiB	−2 B (−0.0%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.5 KiB	55.5 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	8	8	0 (0.0%)	21	✅
Claude	Total thread wire	13.3 KiB	13.2 KiB	−98 B (−0.7%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−100 B (−1.5%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	56.3 KiB	55.5 KiB	−840 B (−1.5%)	66.4 KiB	✅
Claude	Live turn messages	8	8	0 (0.0%)	21	✅

Baseline: 4b75082 · PR result: ce30a73 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.5 KiB
• Claude decoded thread snapshot: 110.2 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[aaditagrawal]

Merge activity

• Sep 2, 8:25 AM UTC: A user started a stack merge that includes this pull request via Graphite.