fix: prevent resolved clarification render loops - #361

Summary

• Prevent session transcripts with resolved structured clarification events from entering React's infinite-render failure path.
• Keep timeline rows as a pure render derivation and restrict semantic row equality to memoized child rendering.
• Add a regression that reproduces the unstable payload identity reported in [Bug][v0.3.0-beta.13] Session thread crashes with React #301 #360 and proves later transcript content still renders.

Root cause

v0.3.0-beta.13 stored derived timeline rows in local React state and called setStableRows() during render whenever computeStableSessionRows() returned a different state object. A resolved data-compozy-event clarification can expose a new structured payload identity on each read, so the comparison never converges. Every render scheduled another render until React stopped the loop with error #301.

Current main had already removed the render-phase setter incidentally in #354, but the stateful stabilization implementation, its implementation-detail tests, and stale documentation remained. That left the failure unguarded and made the unsafe mechanism easy to reintroduce.

Changes

• Regression coverage: add a SessionThread integration case with a resolved clarification whose structured payload has deliberately unstable identity. The test asserts the receipt, answer, and following transcript message render without entering the thread error boundary.
• Timeline architecture: remove StableSessionRowsState, EMPTY_STABLE_SESSION_ROWS, and computeStableSessionRows; rename the remaining module to session-row-equality.ts and keep sessionRowEqual only as the memo comparator for row children.
• Test ownership: remove pure-logic tests that froze the deleted state container's reference behavior. The user-visible render invariant now lives in the canonical component integration suite.
• Internal docs: update the session redesign spec, QA journey, and automation backlog to describe semantic row equality and mounted-DOM stability instead of cross-render object identity.

Compozy Impact Audit

• Native tools: no impact — checked compozy__* IDs, toolsets, descriptors, schemas, digests, risk flags, diagnostics, and capability gates; this is confined to the Web transcript renderer.
• Extensibility and hooks: no impact — no extension, hook, skill/capability, tool/resource, registry, bridge SDK, MCP sidecar, or config lifecycle contract changed.
• Workspace data isolation: no impact — session transcript ownership and workspace_id propagation through CLI/HTTP/UDS/core/store/Web/SSE/cache/events are unchanged; the change only removes local derived render state.
• Official Compozy skill: no impact — no public behavior, tool ID, CLI path, hook event, capability, extension resource, or memory/network/task semantic changed.
• Web/Docs: Web regression coverage and internal architecture references updated; no packages/site documentation impact.
• Settings: no impact — no config.toml key or settings attachment references the removed render-state implementation.

Release Notes

🐛 Bug Fixes

• Prevent resolved clarification receipts from crashing the session timeline with React error feat: add Loop lifecycle controls and surfaces (stack 2/3) #301.

QA

No scenario was added or reset because the production behavior on current main already uses pure derivation; this PR locks that behavior with a regression and removes the obsolete state mechanism. The existing clarification round-trip remains owned by docs/qa/scenarios/RT-session-clarification-roundtrip.md.

Test plan

• Red/green mutation proof: the regression fails with the exact beta.13 render-phase state loop (Too many re-renders, AssistantMessageTimeline, thread error boundary) and passes after restoring pure derivation.
• Focused component and timeline suites: 84 tests passed.
• make gate: Web lint, typecheck, and full Web tests passed; fingerprint 85ba1fc2414f13df5fad9c4b912ed65be3570202.
• React Doctor changed-scope scan: 100/100, no issues.
• make gate-full: delegated to CI by maintainer direction; the local run was intentionally interrupted rather than reported as passing.

Closes #360

Summary by CodeRabbit

• Bug Fixes
  • Improved timeline rendering for resolved clarifications with changing structured data.
  • Ensured resolved receipts, selected answers, and subsequent assistant messages render correctly without triggering an error boundary.
• Performance
  • Refined row comparison for more reliable memoized rendering and live timeline updates.
• Tests
  • Added regression coverage for volatile clarification payloads.
  • Updated streaming rendering tests to validate semantic row equality and nested updates.