Task: Show assistant progress messages

Identity

Task ID: 20260831-show-progress-messages-a14f9c2d
Mode: Feature
Branch: codex/20260831-show-progress-messages-a14f9c2d-show-progress-messages-a14f9c2d
Worktree: /Users/inmanx/Documents/makelore-show-progress-messages-a14f9c2d
Base commit: 38f85f6b5e
Owner: codex
Status: Ready for Integration

Identify the protocol and UI classification of assistant text emitted before or between tool calls, using the supplied screenshot only as a visual example.
Verify that this stage/progress narration is projected and rendered in the current Makelore Code timeline without exposing Pi-private wire types.
Preserve per-item expand/collapse after a stage explanation has completed, including after the enclosing turn has settled.
Make every collapsed thinking, stage-explanation, and tool-output preview start from its first visible block and line, including horizontally overflowing text.

Preserve the product-neutral ConversationMessageNode / Snapshot / Patch contract and the Main-owned Pi boundary.
Keep private reasoning distinct from user-visible assistant narration and tool execution output.
Do not modify the occupied primary worktree or the separate running development worktree.

Confirmed the raw message is an ordinary Pi assistant message whose turn ends with stopReason: toolUse; Main normalizes it to an assistant ConversationMessageNode with stopReason: tool-use.
Confirmed the Renderer semantically projects non-final assistant text as assistant-commentary / “过程说明”, rather than treating it as hidden thinking or as a tool node.
Confirmed active process groups open automatically and show a compact one-line stage explanation with an expand control; settled process groups retain the explanation behind their collapsed process summary while the final assistant answer remains visible.
Added explicit regression coverage proving a completed stage explanation remains collapsed to its first line by default, retains its own expand control, reveals the complete Markdown body, and can be collapsed again.
Changed collapsed process preview selection to use the first displayable block and first non-empty line for thinking, assistant commentary, and tool output. Long lines retain their beginning and use a trailing ellipsis.
Kept every collapsed preview viewport at horizontal offset zero on content and size changes. Tail-only streaming updates no longer replace or replay an unchanged head preview, while expanded content remains complete.

Installed the existing lockfile with pinned pnpm 10.33.4; 1,015 packages were reused from the local store and no manifest or lockfile changed.
Focused Vitest passed: 3 files / 28 tests covering live Pi event projection, durable session hydration, and Coding timeline process/commentary rendering.
Follow-up focused Vitest passed: 1 file / 9 tests, including completed commentary expand/collapse and stable head-preview assertions across streaming updates.
pnpm run typecheck: passed.
Scoped ESLint for the changed Renderer, unit, and Electron E2E files: passed.
pnpm run build:vite: passed; only the repository's existing dynamic-import and bundle-size warnings were emitted.
Focused Electron Playwright E2E passed: 1 file / 2 tests, including first-line thinking display, head truncation, and a measured tool-preview scrollLeft of zero.
Inspected electron/coding-runtime/pi/event-projector.ts, electron/coding-runtime/pi/session-projector.ts, shared/coding-conversation-contracts.ts, and src/pages/Chat/CodingConversationTimeline.tsx across the complete classification path.