fix: restore ACP chat bindings and preserve pending canvas edits

[cxxxxxn (cxxxxxn)]

Summary

• Resolve established Question conversations from their durable owner binding so ACP identity and follow-up routing survive refresh.
• Apply non-content node updates without overwriting pending local content; compare JSON metadata by value using fast-deep-equal.
• Preserve the original user baseline across sequential AI note edits, and remove pending modified markers when an AI rewrite restores that baseline without rewriting operation history.
• Add regression coverage for JSON round trips, nested metadata changes, normalized Markdown restoration, duplicate blocks, and preservation of other pending provenance records.
• Update the corresponding architecture documentation.

Validation

• pnpm typecheck: passed across the repository.
• pnpm format: completed; formatter changes included.
• pnpm lint:fix: completed with warnings, no errors.
• Shared package full suite: 383 tests passed.
• Related web store, save queue, conversation-owner, and provenance suites: 71 tests passed.
• git diff --check: passed.

Scope

Includes the three existing branch commits plus the review follow-up fixes. No real ACP service/browser end-to-end run was performed.

Related issues

Fixes #141.

Related to #172 and #98: this PR addresses false content-conflict detection for non-content updates, but does not resolve genuine label/content conflicts or the broader parallel-write/version-gap behavior. These issues should remain open.

[Copilot]

🟡 Changes recommended

Three unresolved moderate findings affect delta performance, binding precedence, and provenance restoration.

Get a fresh assessment by requesting another Copilot review.

Pull request overview

Restores durable ACP chat bindings, preserves pending canvas edits during sync, and improves AI note provenance handling.

Changes:

• Restores durable Question-node bindings.
• Prevents lifecycle deltas from overwriting pending local content.
• Preserves provenance baselines across sequential AI edits.
• Adds dependency updates, regression tests, and architecture documentation.

File summaries

File	Reviewed change
pnpm-lock.yaml	Locks the deep-equality dependency.
packages/shared/src/types/canvas/node.ts	Updates provenance contracts.
packages/shared/src/canvas-engine/provenance/noteProvenance.ts	Preserves and clears AI provenance. Moderate, 2 votes: Preserve the baseline canonical key or compare against full-document definitions to handle reference-style syntax correctly.
packages/shared/src/canvas-engine/__tests__/noteProvenance.executor.test.ts	Adds provenance regression coverage.
docs/architecture/question-node.md	Documents durable binding replay.
docs/architecture/note-node.md	Documents provenance restoration behavior.
docs/architecture/canvas-realtime-sync.md	Documents lifecycle delta merging.
apps/web/src/utils/__tests__/blockProvenance.test.ts	Tests provenance edge cases.
apps/web/src/store/conversationOwner.ts	Adds durable binding resolution. Moderate, 1 vote: Restrict binding precedence to established/fixed conversations so editable threads honor updated selections.
apps/web/src/store/conversationOwner.test.ts	Tests binding resolution.
apps/web/src/store/canvasStore.ts	Preserves pending content during delta application. Moderate, 1 vote: Construct localNodesById lazily to avoid unnecessary O(n) work on clean canvases.
apps/web/src/store/canvasStore.agentDeltaConflict.test.ts	Tests delta conflict behavior.
apps/web/src/hooks/useAgentStream.ts	Uses durable bindings for requests.
apps/web/src/components/Panels/ChatPanel/index.tsx	Hydrates bindings synchronously.
apps/web/package.json	Adds fast-deep-equal.

Review details

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

Suppressed comments (2)

apps/web/src/store/canvasStore.ts:1574

• localNodesById is allocated by scanning every canvas node before the dirty.size === 0 fast path is selected, and it is never read for the usual clean-canvas case. Every incoming agent delta batch therefore pays O(number of nodes) work introduced by this change; make the lookup lazy or construct it only when dirty.size > 0.

      const preservedPendingNodeIds = new Set<string>();
      const localNodesById = new Map(
        get().nodes.map((node) => [node.id, node]),
      );

apps/web/src/store/conversationOwner.ts:127

• This unconditionally treats any source.agentBinding as authoritative, but ChatPanel still exposes the selector for selectable Question nodes with no user messages. For a selectable/idle node that already has a binding, choosing another agent only updates the cache; this function keeps returning the old node binding, and the first send routes with it again. Restrict owner precedence to established/fixed conversations (or pass the compose state) so editable threads continue to use their cache binding.

export function resolveConversationAgentBinding(
  source: ConversationOwnerSource | undefined,
  cachedBinding: AgentBinding,
): AgentBinding {
  return source?.agentBinding ?? cachedBinding;

• Files reviewed: 14/15 changed files
• Comments generated: 1
• Review effort level: Lite

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