SPEC v0.6: M4 decisions (D-035 to D-039), HANDOFF rewritten

- D-035 unusable mutation_id/entity_type/entity.id fails the whole push with 400; other shape errors per mutation.
- D-036 0 mutations is batch_too_large ("outside 1 to 100").
- D-037 never-synced delete runs full step-8 validation; current on every rejection; created_at kept; canonical ids.
- D-038 FCM retries: one send plus three retries (1/5/25 s), 401 drops the token, other 4xx not retried.
- D-039 pruning strictly older than 90 days; tasks::start returns AppState with the push queue, SqlAuditWriter default.
- Clarifications: step 8 order, negative since, pull read transaction, FCM JWT kid and cache, token clearing only if
  unchanged, unusable credentials, scheduler clock jumps, rotate-epoch exit codes, /i/ empty code, image build needs
  a C toolchain and CA roots (dev image rebuilt 2026-10-18).
- PLAN-M4 pruning wording, prompts/README status, HANDOFF at bd6f10a.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQd3pEP9UeN2uifbHknQ7B

prompts/README.md

@@ -2,7 +2,7 @@
 
 One ready-to-paste start prompt per plan (`PLAN-<id>.md` at the repository root), plus `ORCHESTRATOR-prompt.md`. Before pasting, the orchestrator fills `{{NEXT_DECISION}}`, `{{SPEC_VERSION}}`, `{{SCHEMA_VERSION}}` (disjoint ranges for agents that run in parallel, CLAUDE.md › Numbering) and `{{ORCHESTRATOR_NOTES}}` (answers to the plan's open points, phone assignment, overrides). `U2.md` also takes `{{OWNER_PICK_AND_COMMENTS}}`. U1 and U2 run in the owner's own Claude session in `~/orca/workspaces/kvitt/UX-sprint` on branch `UX-sprint`. The numbers are for proposed entries in agents' reports: implementation agents never edit `SPEC.md` or `docs/decisions.md`; a docs agent records what the orchestrator accepts (CLAUDE.md › Orchestration).
 
-Dependencies follow SPEC §11.1 and §11.2 (v0.5). Status as of 2026-10-17: M0 done, M1 landed (`c6df2ab`), M2c-dev landed (`c885aba`), M2a landed (`fdf2093`), M2b landed (`fad6fc9`), M3 landed (`503cee5`), M5 landed (`c28c52b`); M4 in flight; U1 in the owner's session. The plans' open points are resolved in SPEC v0.3 and recorded in each plan's §4; v0.4 records the M2a and M2b decisions (D-005 to D-014); v0.5 the M3 and M5 decisions (D-026 to D-034, D-040 to D-043; D-035 to D-039 reserved for M4).
+Dependencies follow SPEC §11.1 and §11.2 (v0.6). Status as of 2026-10-18: M0 done, M1 landed (`c6df2ab`), M2c-dev landed (`c885aba`), M2a landed (`fdf2093`), M2b landed (`fad6fc9`), M3 landed (`503cee5`), M5 landed (`c28c52b`), M4 landed (`bd6f10a`); M9 in flight; U1 committed on `UX-sprint` (owner's direction pick pending). The plans' open points are resolved in SPEC v0.3 and recorded in each plan's §4; v0.4 records the M2a and M2b decisions (D-005 to D-014); v0.5 the M3 and M5 decisions (D-026 to D-034, D-040 to D-043); v0.6 the M4 decisions (D-035 to D-039).
 
 ## Dependency order and waves
 
@@ -17,7 +17,7 @@ Plans in the same wave can run in parallel (they own disjoint paths, SPEC §14.7
 | 1 | M2c-dev Infra for development | `M2c-dev.md` | M0 (its health check needs M2a's image) | done (`c885aba`) |
 | 1 | U2 UX design spec | `U2.md` | U1 and the owner's pick | M2a, M2b, M2c-dev, wave 2 |
 | 2 | M3 Server core API | `M3.md` | M2a | done (`503cee5`) |
-| 2 | M4 Server sync, audit, push, scheduler | `M4.md` | M2a; lands after M3 (D-015) | M3, M5, M6 |
+| 2 | M4 Server sync, audit, push, scheduler | `M4.md` | M2a; lands after M3 (D-015) | done (`bd6f10a`) |
 | 2 | M5 Android data layer | `M5.md` | M1, M2b | done (`c28c52b`) |
 | 2 | M6 Design system | `M6.md` | U2 approved, M2b, the §9.7 colour spec change | M3, M4, M5 |
 | 3 | M7a Feature onboarding | `M7a.md` | M6 | M7b to M7f, M9 |