Plan: Update migration-from-legacy.md to implemented status#

Summary#

Update docs/migration-from-legacy.md to reflect the completed shell-to-agent-core migration (2026-03-16). The document currently describes the migration as in-progress with draft language; it needs metadata updates, PM workflow corrections, hook behavior documentation, router routing details, and a migration completion note.

Files#

Steps#

1. Update metadata header — change last-updated to 2026-03-16, add status: implemented field to the YAML frontmatter.
2. Update refine phase description — add documentation of the conversational PM workflow (question-and-answer rounds with the issue author) in the TLA Flow or a new "Refine Phase" subsection.
3. Document PhaseHooksService refine hook — add that the refine hook removes the in-refinement label and moves the issue to AgentQueue status; clarify that no refined label is used in the hook flow.
4. Update router section — document that issue_comment events are routed based on in-refinement label presence (if label present → refine phase; otherwise → directive handling).
5. Remove or correct stale references — remove references to refined label in the "Labels Kept by TLA" table; replace any "draft"/"in-progress" migration language with "implemented" language; update "Labels Deprecated by TLA" section to include awaiting-plan-approval.
6. Add migration completion note — add a section confirming all 17 WAL issues were completed and merged as of 2026-03-16, closing out the migration.

Verification#

• All acceptance criteria from the issue are addressed in the updated document.
• No references to refined label remain except in the Legacy Labels table.
• Metadata header reflects status: implemented and last-updated: 2026-03-16.

Risks#

• The awaiting-plan-approval label appears in both "Labels Kept by TLA" and may need to move to "Labels Deprecated" — will verify against issue requirements.