v1.29.0 — pi-plan-build

• /pb:fix [ids]: fix review findings in a fresh fenced session — seed, fence and completion report, then /pb:review checks the delta. Unknown ids refused, never guessed; laps repeat to a cap of 3 then escalate as silent or stuck; spec-revision items never start a lap.
• Spec-review gate: fresh eyes attack the ready spec's Decisions before the first task — P0/P1 block T1 until amended or rebutted (exactly once, never re-gated); P2/P3 travel on with the build for the code reviewer.
• Acceptance↔test mapping: every - Acceptance: line on a tested task names its proof (tests: …) or its exemption (non-testable: why) — enforced at write time, and faked or dodged mappings are P1 at review. Tasks without a Test: line stay covered by the gate suite and never block docs or config changes.
• Store races closed: planning sessions, review sessions, pending builds and fixes sessions are per-session files (migrated once from the legacy maps); asked.json is append-only. Parallel sessions stop clobbering each other's state.
• Clearer handoffs: plan args are one-lined and capped with disclosure; near-miss spec names redirect instead of starting silent duplicate plans; planning gets a widget; /pb:build validates names, records trailing guidance, warns on a misplaced --fresh, confirms takeovers, and refuses a readable file under an invalid name; a mid-build review can no longer strand the build as reviewed; all What-now blocks rewritten in plain language with an example each.