[tianxiaochannel-oss88]

Summary

• Adds canonical Channel conversation APIs around LingThread, LingTurn, and ConversationItem, with explicit Root, Topic-anchor, and Thread surfaces.
• Moves transcript projection, reply linkage, streaming, edits, paging, and Web refresh behavior onto canonical items and turns.
• Removes the legacy Channel message runtime authority and v1 intent compatibility paths while retaining one-time SQLite migration and recovery support.
• Adds safe Context inspection and revision-fenced segment correction without exposing prompts, hidden reasoning, secrets, or private teammate memory.
• Tightens the public Turn trust boundary so clients cannot forge authorship, intent, Task linkage, Run linkage, or mixed Item/Thread identity.
• Updates the Continuity v2 design and adjacent Channel architecture documents to match the shipped contracts.

Test Coverage

All new critical paths have automated coverage, including:

• Root, Topic, and Branch Thread resolution and navigation.
• Stable item paging, Turn lifecycle, idempotency, migration rollback, and recovery.
• Issue [Bug]: Channel intent selector repeats generic clarification after content continuation #421 content continuation versus explicit file execution.
• Strict public request parsing and forged-authority rejection.
• Streaming, pending-send acknowledgement, reconnect, edits, and canonical reply lineage.
• Context correction races, private-memory redaction, summary recovery, and multi-agent projection consistency.

Pre-Landing Review

No unresolved findings. SQL/data safety, concurrency, LLM trust boundaries, enum consumers, API contracts, Web state races, performance, and legacy-authority cleanup were reviewed against the final diff.

Design Review

Lite design review: no issues found. This change reuses existing Channel UI surfaces and introduces no new CSS or visual system.

Eval Results

Provider-independent semantic fixtures cover Chinese and English continuation, topic switching, ambiguous references, content generation versus execution, explicit commands, inaccessible Segment ids, and multi-agent privacy. No paid live-provider call is required for this merge gate.

Scope Drift

Scope Check: CLEAN. The diff completes S7 API/Web/authority cleanup and does not introduce a second timeline store, compatibility layer, new infrastructure, or unrelated UI redesign.

Plan Completion

Continuity v2 implementation tasks G0 and T0-T8 are complete. No architecture, ownership, or product decisions remain unresolved.

Verification Results

• Contracts: 36 passed
• Core: 362 passed
• Daemon: 905 passed
• API Client: 49 passed
• Remote Protocol: 40 passed
• Web unit: 45 passed
• Channel E2E: 113 passed
• Adjacent Channel E2E: 15 passed
• Web typecheck, i18n, and lint: passed
• Public-repository safety: 3,034 files checked, passed
• Markdown links: 236 files checked, passed
• Legacy authority audit and git diff --check: passed

Documentation

Updated the daemon API reference, Continuity v2 owning design and implementation plan, Channel streaming, intent selection, session, governance, shared conversation capabilities, and implementation status.

Closes #421