feat(chat): adopt upstream rendering and client sync improvements

[rynfar]

Large conversations repeatedly reparse completed Markdown and code, rebuild HTTP handlers and publish each streamed event separately. This ports the frozen upstream chat and client improvements: completed content and code-line DOM are reused, thread switches hold a bounded painted timeline, remote requests build only their needed API group, and queued stream events publish as a batch while preserving snapshot/revert/delete ordering.

The same dependency group adds expandable question-answer tool rows, image zoom/pan, touch copy controls, available-width model labels, environment search descriptions, Linux terminal middle-click paste, unpriced usage and live countdowns, diff palettes, platform Open icons, and sidebar/panel presentation fixes.

Pylon adaptations retain Prime/provider admission and session controls, typed message-ID rewind and rollback safeguards, per-turn reported costs, image resource resolution, worker cleanup, and reduced-motion/background/focus gates. Held content from a different thread disables mutation callbacks and live work status, uses its environment/path context, and does not cache ephemeral preview URLs. Remote cookie, bearer and DPoP refresh/retry behavior remains intact.

Owning cycle: #497. Frozen range: 6c583620ff7ad3235b135af7107c0543467eecfa..4a4c6dd2adc350a68ba18bb28b24b5a7e4660dab. All 26 assigned sources below are adopted with Pylon adaptations; none deferred. Companion mobile source 2ebc9fa4ed24e389eef24039f27c73ae6633858f contributes the userInput.ts Hermes-compatible sort hunk here; its remaining hunks are owned by the mobile lane.

Full upstream source	Behavior	Outcome
50f918c57a2df85bd97612b958386aaca035dcab	fix(web): allow expanding duplicate tool call commands (#10981)	Adopted
8d8189e67dc091ffb91df451c9a957bbd68a5364	feat(web): zoom and pan expanded images (#10869)	Adopted
b7b3ef1e6fcb5c22a9790d2578fe8af7ce396835	fix(ui): use available space for composer model names (#11002)	Adopted
385cc0a4c669aeae786ad47bfe3ecbbc352eff24	fix(web): show message copy buttons on touch devices (#11020)	Adopted
d1eeb16247a0bd2eca8bbbfa5ab777e096af949c	fix(web): middle-click pastes in the terminal on Linux (#11018)	Adopted
bb5e824c9fcbd76c93ef15b304f89f8b6999f32c	feat: add blue and orange diff color palette (#10671)	Adopted
21a5ccf881abc3aa8b5ea9de4a65edbb6ceadbda	fix(web): prevent seams in the topbar scroll fade (#10914)	Adopted
21d744039bf76c072c875886ee497e391a0dd430	fix(web): fit provider update text inside sidebar notices (#11034)	Adopted
502131adff7494d1a1797b4fe518870f7e8431fd	fix(web): collapse a tool call by clicking its expanded label (#11017)	Adopted
c52b8d96e4b34201f19b5e5bb12c6b2a77bfaa9a	feat(command-palette): show environments in search results (#10722)	Adopted
27eb79dc719d70a99db495b0cb20bd6e3ac10b8d	fix(chat): fold question answers into tool activity (#11014)	Adopted
48654c1182c41dbd5e99ef0d6620a13ba2400f26	fix(usage): flag unpriced model activity instead of showing $0.00 (#11021)	Adopted
8fc253605e6d203c3654dbb1ce22fa1fd6fa0767	perf(web): format minimap previews only when opened (#11181)	Adopted
a9dabbf100d1f6c0b2ed7b5e879d469ac14fd186	perf(web): reuse completed Markdown prefixes while streaming (#11193)	Adopted
d7d7f8f3eb7bf593925281eb62348e15a91252b8	perf(web): resume syntax highlighting from completed lines (#11196)	Adopted
8078c532ceeee5cb951325031f216171507f3d5e	perf(web): preserve completed code-line DOM while streaming (#11198)	Adopted
211618fd9fe39d3dde01171a6856ce9f633571c9	perf(web): huge-thread switch no longer blanks the chat pane (#11169)	Adopted
fb3d165d33b155038de717851207d25fb52fe65e	fix(web): show platform file manager icons in Open menu (#11228)	Adopted
2b7d3a45e6ee9454e4dd46aaf0276ca05d8555d3	perf(web): avoid scanning chat history for sidebar backgrounds (#11206)	Adopted
6e8931d75615ec020e602e97df2694b0541a6272	perf(client): reduce remote request and message sync overhead (#11029)	Adopted
e1c94f703f05b43f2935d09ed1ef882d0ee13ff8	fix(web): refresh usage limit countdowns without switching tabs (#11187)	Adopted
e145c5f22a10d7433420b447537ed3f29a66d7d9	perf(client-runtime): speed up message sync on desktop and mobile (#11302)	Adopted
867eb9bffc1e46ce0f7493ae760f9eb9d9dec3a8	fix(web): themed panel toggles show their disabled state (#11188)	Adopted
50791a0530a9c4eed7924dbfedf2fcf430d4ed98	fix(web): use branch wording in commit dialogs (#11281)	Adopted
8a2d5f545ae1f76d08a6a6515f6b6c383cada5ad	fix(test): drain worker broadcasts before restoring browser globals (#11349)	Adopted
38827789c4de97955315b459cb3b0b8207f692d8	fix(web): keep sidebar scroll position when pinning threads (#10757)	Adopted

Validation: 605 focused changed-file tests pass (including 54 terminal tests under the web Vite configuration); 50 projection/question-folding/stream-lifecycle regressions pass; 317 existing web/mobile work-log, timeline, session and remote authorization integration tests pass. Typechecks pass for web, mobile, desktop, server (t3), client-runtime, contracts and shared. Targeted lint passes with existing warnings; all changed files formatted, frozen lockfile install and diff whitespace checks pass. Added explicit server projection idempotence/choice-slimming and shared folding tests. Initial failures were an outdated usage useState mock after adding countdown state, an upstream benchmark fixture's not-yet-integrated PR array, and invoking the WASM terminal suite without the web configuration; all are corrected in final verification.

UI evidence limitation: this turn has no browser/computer-use authorization, so final integrated Pylon screenshots/video have not been captured. Existing render/DOM-identity tests verify the affected rendering paths. Upstream reference evidence is available in thread switching #11169, question folding #11014, and image zoom #10869; these are upstream evidence, not Pylon verification. No end-to-end performance numbers or native UI rendering are claimed. Peer adversarial review and final-head CI are required before merge.

Model: GPT-6. Harness: Codex.

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Project	Deployment	Actions	Updated
pylon-marketing	Ready	Preview	Sep 12, 2026 6:24am UTC

[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	14.1 KiB	14.1 KiB	+31 B (+0.2%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.2 KiB	7.2 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.9 KiB	6.9 KiB	+29 B (+0.4%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	58.8 KiB	58.8 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	10	10	0 (0.0%)	21	✅
Claude	Total thread wire	14.1 KiB	14.1 KiB	+7 B (+0.0%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.2 KiB	7.2 KiB	0 B (0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.9 KiB	6.9 KiB	+7 B (+0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	59.7 KiB	59.7 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	10	10	0 (0.0%)	21	✅

Baseline: f3402be · PR result: aa29544 · 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: 115.6 KiB
• Claude decoded thread snapshot: 116.3 KiB

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

[rynfar]

Adversarial review completed by the independent devices lane on head aa29544: no blocking findings after checking grouped HTTP/auth retries, endpoint routing, message deletion/revert/pagination ordering, incremental Markdown invalidation, held-thread isolation, tool folding, remote palette targets and media. 972 focused tests, seven consumer typechecks, scoped lint/format and all final-head CI checks passed. Final Pylon visual/native evidence remains unperformed as recorded in the PR. Landing under the standing upstream-cycle approval.