Lane F ratchet coverage: include AI server cognition shims

[joelteply]

Problem

PR #1401 added the persona TS cognition ratchet for six watched directories under src/system/user/server. During PR #1402 validation, running the ratchet refresh produced no meaningful baseline change after deleting about 115 lines from src/system/ai/server/AIDecisionService.ts.

That means the current ratchet does not mechanically lock deletion gains in the AI server shim surface. The code is moving in the right direction, but the ratchet coverage is narrower than the AIRC discussion assumed.

Required outcome

Expand Lane F ratchet coverage or add a sibling ratchet so runtime cognition shims under src/system/ai/server cannot grow after Rust migration.

Constraints

• Do not block generated/type-only files unnecessarily.
• Do not reintroduce TypeScript cognition logic.
• Keep runtime cognition Rust-owned; TS may remain as thin IPC transport only where still required.
• Add tests proving growth in AIDecisionService.ts or new verb-shaped AI server TS fails.

Evidence

• PR feat(lane-f): persona-ts cognition deletion ratchet — PR-1 script #1401 baseline: 8583 LOC across six watched dirs.
• PR feat(cognition,#1385): generate_response PR-3 — TS shim + delete dead TS (PR-4 folded) #1402 deletion: AIDecisionService.generateResponse shim plus dead prompt builder deletion, but baseline refresh only changed timestamp/order and was reverted.

Validation target

• The ratchet test suite or successor test covers the AI server shim path.
• The ratchet check fails when AI server cognition TS grows without an explicit allowlist entry.