feat: implement PI core chat timeline

.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md

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+# Task: Implement PI-120 core chat and first-conversation UX
+
+## Identity
+
+- Task ID: 20260823-pi-chat-timeline-c8f31a62
+- Mode: Feature
+- Branch: codex/20260823-pi-chat-timeline-c8f31a62-pi-chat-timeline
+- Worktree: D:\Datas\OthersProjects\makelore-pi-chat-timeline-c8f31a62
+- Base commit: 54d8bb2e4a6f1a7dd857827659e60d1b4a1fb6f5
+- Owner: codex-root
+- Status: In Progress
+
+## Scope
+
+- Implement `PI-120 — Core Chat and first-Conversation UX` on cumulative
+  PI-110 delivery HEAD `54d8bb2`.
+- Add a vendor-neutral `CodingChatPanel` composition, first-Conversation
+  metadata selection/creation, core Composer, and memoized timeline renderers
+  for message/thinking/tool/compaction/boundary nodes.
+- Bind the page exclusively to `/api/coding/*` Renderer facades and the
+  PI-110 Conversation store, including optimistic prompt acceptance,
+  preparing/queued/running/error/recovery states, draft continuity, and
+  hidden-Conversation render isolation.
+- Add focused component/performance coverage and the first-prompt Electron E2E.
+  Do not implement PI-130 feature-complete controls or PI-140 legacy removal.
+
+## Intent And Constraints
+
+- The exact Ready Frontier is `{PI-120}`. PI-110 is Done at audit HEAD
+  `934ba02` and cumulative delivery HEAD `54d8bb2`; PI-130 remains locked until
+  this ticket is accepted.
+- Textarea editability depends only on an active project, an enabled Agent,
+  and the absence of a project destruction/migration transition. It never
+  depends on worker/runtime/metadata loading, provider latency, diagnostics,
+  another Conversation, or the current Conversation run state.
+- Conversation creation is local metadata only. Snapshot/prewarm is lazy and
+  Conversation-scoped; preparation beyond ten seconds becomes a recoverable
+  error while the draft stays editable.
+- A send immediately creates one stable optimistic user node. HTTP 202 is only
+  acceptance; later provider/tool failure never removes the accepted user
+  message, and uncertain delivery is never silently resent.
+- Renderer components must use granular PI-110 selectors and memoized blocks.
+  Hidden Conversation streaming cannot rerender the selected timeline;
+  cumulative tool output replaces rather than appends duplicate content.
+- Do not read `src/stores/opencode.ts`, call `/api/opencode`, import Pi/OpenCode
+  wire types, or mechanically rename the legacy 4k-line panel. The old panel
+  remains only as PI-140 removal residue after the new page composition takes
+  ownership.
+- PI-130 still owns model/thinking controls, steer/follow-up queue controls,
+  compaction/retry/context actions, interactions, subagent graph, changes/files/
+  browser/skills/commands, and Conversation archive/fork/title/unread UI.
+- The planner amended the attachment contract: `POST /api/coding/attachments`
+  accepts one bounded image binary and returns only `{attachmentId,mime,byteLength}`;
+  authenticated `GET /api/coding/attachments/:id/content` returns raw bytes.
+  Upload happens only on Send, each local variant has one in-flight/result, and
+  Renderer state/protocol keep references rather than base64.
+- The planner selected public `patch-batch` delivery only. Main retains private
+  single-patch envelopes and original seq, batches per Conversation/generation
+  for 16–33 ms with bounded early flush, and cancels an old generation's pending
+  batch. Renderer validates the full batch and folds it in one Zustand
+  transaction; malformed/gapped batches recover only their target.
+- Real Provider remains Explicitly Waived / Accepted Risk with
+  `realTurnVerified=false`. macOS x64/arm64 remains deferred to mandatory
+  PI-150. Neither is Pass evidence. No subagents are authorized.
+
+## Project Context Loaded
+
+- Task identity: `20260823-pi-chat-timeline-c8f31a62`, feature mode, isolated
+  branch/worktree above, exact base
+  `54d8bb2e4a6f1a7dd857827659e60d1b4a1fb6f5`.
+- Concurrent Task Gate passed. The only semantically adjacent planning task,
+  `20260820-partner-create-model-parity-c83d`, still has undefined scope and no
+  claimed files. The canonical main integration task is Blocked and is not a
+  write target; all other planning owners are unrelated Canvas/Robot/Learning
+  or read-only scopes.
+- Planning Gate inputs read: memory index, active task record, project
+  positioning/current state/decision/system/architecture/domain documents,
+  PI-100/105/110 completion records, exact PI-120 ticket and PI-130 boundary,
+  and relevant `UX-*`, `REN-*`, API, performance and recovery Spec sections.
+- Canonical positioning and project-level success fields are placeholders and
+  the integrated memory still describes the legacy OpenCode UI. Repository
+  guidance plus the planner-owned Pi Spec/tickets and reviewed cumulative code
+  are authoritative for this feature branch.
+- Confirmed seams: schema-v2 project/config/Conversation routes already provide
+  local-only metadata; PI-110 provides the typed Snapshot/prompt/SSE facade,
+  shared reducer, per-Conversation store, optimistic identity, target-only
+  recovery, and granular selectors. The current Chat page still imports the
+  legacy `OpencodeChatPanel` and is the cutover seam.
+- No accepted ADR conflicts with this ticket. The attachment transport gap is
+  recorded above and has been escalated to the planner instead of silently
+  inventing a route.
+- Gate result: Passed.
+
+## Plan
+
+1. Add the minimal vendor-neutral project/config/Conversation Renderer facade
+   and metadata store needed to load the active project, enabled Agents and
+   Conversations without touching the legacy OpenCode store.
+2. Build a small `CodingChatPanel` composition and switch the Chat page to it;
+   make first-Conversation selection/creation local-only and keep Textarea
+   readiness independent of snapshot/runtime preparation.
+3. Implement focused Composer submission/recovery UI over the PI-110 draft and
+   optimistic request lifecycle, including preparing/queued/running/error
+   status without a page-wide loading gate.
+4. Implement memoized/windowed message, thinking, tool, compaction and boundary
+   blocks that update only the selected target and keep large/cumulative output
+   bounded; apply the planner's attachment ruling without expanding PI-130.
+5. Add red-capable first-Conversation, core Chat, optimistic failure,
+   hidden-Conversation/render-count and 100 KB performance fixtures, plus the
+   first-prompt Electron E2E; then run focused/full validation, build,
+   documentation gates and planner review.
+
+## Outcome
+
+- Replaced the Chat page composition with a vendor-neutral `CodingChatPanel`
+  backed only by `/api/coding/*` facades. It loads active project/config/local
+  Conversation metadata, auto-creates the first local Conversation, and keeps
+  the Composer editable while runtime Snapshot preparation is held.
+- Added text/image Composer behavior, stable optimistic user nodes, distinct
+  preparing/accepted/running/uncertain/error/recovery feedback, Enter/Shift+Enter
+  and IME handling, Send-time single-flight image upload, and authenticated
+  object-URL previews without base64 state or protocol payloads.
+- Added a memoized/windowed timeline for message, Markdown, thinking, tool,
+  compaction, boundary and notice nodes. Hidden Conversation batches leave the
+  selected timeline selector stable; cumulative tool output is replaced rather
+  than duplicated.
+- Added Main-owned attachment binary routes/IPC transport and public Snapshot +
+  `patch-batch` SSE delivery. Main batches at 24 ms by default with item/byte
+  early-flush bounds; Renderer atomically rejects malformed/gapped batches,
+  buffers during target recovery, trims Snapshot-covered items and replays only
+  a strict continuous tail.
+- Fixed a supported concurrency defect exposed by the full suite: the Pi
+  Session Registry now reuses one Conversation store per project, serializing
+  simultaneous first bindings instead of racing writes to the same metadata
+  file.
+- Synchronized `README.md` with the current Pi core Chat, first-Conversation,
+  batch and attachment behavior. PI-130 feature controls and PI-140 legacy
+  removal remain outside this task.
+
+## Verification
+
+- `pnpm exec vitest run tests/unit/coding-workspace-store.test.ts tests/unit/coding-projects-facade.test.ts tests/unit/coding-attachments-facade.test.ts tests/unit/coding-attachments-routes.test.ts tests/unit/coding-chat-panel.test.tsx tests/unit/coding-conversation-timeline.test.tsx tests/unit/coding-conversations-store.test.tsx tests/unit/coding-core-routes.test.ts tests/unit/host-api.test.ts tests/unit/host-api-proxy.test.ts`: passed, 10 files / 68 tests before the final malformed-batch and Session Registry regression additions.
+- `pnpm exec vitest run tests/unit/pi-session-registry.test.ts tests/unit/pi-conversation-runtime.test.ts tests/unit/coding-conversations-store.test.tsx tests/unit/coding-chat-panel.test.tsx`: passed, 4 files / 25 tests.
+- `pnpm test`: passed, 217 files / 2303 passed / 2 skipped. The final run is green after fixing the same-project parallel Session Registry write race and stabilizing the AI Hardware async query at its actual loading boundary.
+- `pnpm run typecheck`: passed.
+- `pnpm run lint:check`: passed with 0 errors and six unchanged warnings in `ExecutionGraphCard`, `Home`, and `Makelore`.
+- `pnpm run build:vite`: passed; existing Vite dynamic-import and chunk-size warnings remain.
+- `pnpm exec playwright test tests/e2e/pi-coding-first-chat.spec.ts`: passed, 1/1.
+- `pnpm exec playwright test tests/e2e/pi-coding-first-chat.spec.ts --repeat-each=20 --workers=1`: passed, 20/20 fresh-userData runs. Every sample asserted Composer editability below 500 ms while runtime Snapshot was held, so the measured sample p95 is below the locked 500 ms budget; the same fixture verifies optimistic prompt visibility and HTTP 202 acceptance without a real Provider.
+- `git diff --check`: passed; only repository line-ending conversion notices were printed.
+- Real Provider remains **Explicitly Waived / Accepted Risk** with
+  `realTurnVerified=false`; no Provider Account, credential isolation,
+  protocol-specific endpoint, rate-limit or real concurrency behavior is
+  claimed as Pass.
+- macOS x64/arm64 execution remains user-deferred to mandatory `PI-150`; no
+  macOS Pass is claimed.
+
+## Follow-ups
+
+- PI-130 owns Conversation model/thinking controls, steer/follow-up queue,
+  compaction/retry/context controls, interactions, subagents, changes/files,
+  browser, skills/commands, and archive/fork/title/unread UI.
+- PI-140 owns removal of legacy OpenCode runtime/routes/dependencies/UI/tests
+  and migration notice.
+- PI-150 must run final packaged cross-platform proof, including the deferred
+  macOS x64/arm64 matrix. Real Provider qualification remains explicitly waived
+  unless the user changes that decision.
+
+## Promotion Candidates
+
+- Preserve the public Snapshot + `patch-batch` hard-cut contract and the
+  target-only recovery semantics in the planner-owned Pi Spec/tickets after
+  implementation review.
+- Preserve the explicit attachment upload/read Host contract, Send-time
+  single-flight rule, and reference-only Renderer state in the planner-owned
+  Pi Spec/tickets after implementation review.