Parent: #1235
Blocked by: #1240

Summary

Complete documentation, add to full feature set, end-to-end integration test.

Branch: feat/m33/orchestration-docs

Deliverables

New files

• docs/src/advanced/task-orchestration.md — user documentation

Modified files

• docs/src/SUMMARY.md — add task orchestration chapter
• Root Cargo.toml — add orchestration to full feature list
• CHANGELOG.md — document new feature
• Root README.md — mention orchestration capability

Documentation contents

• Overview: what task orchestration does
• Quick start: /plan command usage
• Config reference: all [orchestration] options
• DAG concepts: tasks, dependencies, failure strategies
• Examples: simple goal → DAG → execution
• Limitations: no nested sub-graphs, no dynamic re-planning

Tests (~5)

• Integration test: end-to-end plan → execute → aggregate (MockProvider)
• Feature flag: compiles without orchestration feature
• Feature flag: compiles with orchestration feature
• Feature flag: /plan command unavailable when disabled

Dependencies

Blocked by: Phase 5 (#1240)
Can run in parallel with: Phase 6 (#1241)