feat(cli): `os migrate meta --write` — the AST codemod that rewrites authored sources for the mechanical `applied` set (v18)

[os-support-ai]

Commissioned by maintainer ruling on #9529 (2026-08-18, live PM chat with the triage seat, session session_01EUZUjvnLsqwHVkXkTv8TKQ; verbatim: 「其他接受你的建议」— Option 2 now, Option 1 as a v18 Feature). This card is Option 1.

Scope

Implement the in-place rewrite that the retirement prescriptions promise: an AST codemod (ts-morph is already a packages/cli dependency) over objectstack.config.ts and per-artifact authored modules (defineView / defineAgent / defineFlow shapes), covering the mechanical applied set only — the chain's semantic TODOs stay manual, exactly as #9529 records. Suggested flag shape: --write (in-place) alongside the existing --out snapshot; dry-run remains the default.

When this lands, the shared retirement sentence in packages/spec/src/shared/retired-key.ts (reworded to the honest replay-and-print statement by #9529's Option-2 half) may be restored to the automatic-rewrite claim it then honestly makes — that restoration belongs to this card's PR, in lockstep with the class-wide pin.

Scheduling

Deliberately not current-cycle work.

Restart-when: the v18 major development cycle opens (first v18 changeset-major accepted on main), or a maintainer instruction pulls it forward

Refs

#9529 (the promise-vs-tool gap and its measurement) · #9418 (the load-refusal half this builds on) · #6856 (the 2026-08-09 sentence ruling).

[objectstack-fleet]

Triage: hold released, pm:on-hold → pm:queue, graded priority:p3. The body's Restart-when: lets a maintainer instruction pull it forward, and that instruction was given

Triage seat (objectstack-wide, seat post #6015) · session_01AavokzJ5DndAwitDXvKy4U · 2026-10-07T13:25Z. ⛔ Not a claim, ⛔ not a dispatch.

Released on the maintainer's order in the triage seat's chat: 「你应该先解锁 v18 所有的卡片」, then 「同意」 to the plan. #15193 (the v18 gate) closed on that word (6037915987). The ruling record is #22050 6037890422, and the opening card is #22080 (Changesets pre mode).

• Restart condition (the body): "the v18 major development cycle opens …, or a maintainer instruction pulls it forward".
• Scope stands as commissioned (os migrate meta never rewrites the authored sources that 144 shipped retirement messages promise it will #9529, Option 1):
  • an AST codemod (ts-morph) over objectstack.config.ts and the per-artifact authored modules, covering only the mechanical applied set;
  • --write beside --out, with dry-run still the default;
  • the restoration of the shared retirement sentence (packages/spec/src/shared/retired-key.ts) rides this PR.
• Why p3: authors already get the replay-and-print path. This adds the in-place rewrite it promises.
• Clause-②: yes (a new CLI flag). A contract review is owed at the PR.