tasks: decompose Phase 0a ADR foundation and mark prior tasks completed

Add 10 new tasks under tasks/architecture/ for Phase 0a (ADR writing):
- 9 ADR tasks (026-034) with dependency-ordered structure
- 1 review checkpoint task before Phase 0b spec writing

ADR dependency graph (3 generations):
  Gen 1 (parallel): 026, 029, 030, 031, 032, 034
  Gen 2 (depends on 029): 027, 028
  Gen 3 (depends on 027+028): 033
  Gen 4: review checkpoint

Also mark all 34 prior implementation tasks as completed — they
were finished but still showing as pending in the taskgraph.

tasks/architecture/review-adr-foundation.md

@@ -0,0 +1,51 @@
+---
+id: architecture/review-adr-foundation
+name: Review Phase 0a ADRs — foundation decisions before spec writing
+status: pending
+depends_on:
+  - architecture/adr-034-head-worker-terminology
+  - architecture/adr-032-event-boundary-discipline
+  - architecture/adr-029-identity-core-type
+  - architecture/adr-030-static-dynamic-config-split
+  - architecture/adr-031-forwarding-policy
+  - architecture/adr-028-auth-irpc-service
+  - architecture/adr-027-crate-decomposition
+  - architecture/adr-026-transport-interface-separation
+  - architecture/adr-033-operationenv-irpc-call-protocol
+scope: broad
+risk: low
+impact: project
+level: review
+---
+
+## Description
+
+Review all Phase 0a ADRs (026-034) before proceeding to spec writing (Phase 0b). This is the critical checkpoint where we validate that the architectural decisions are consistent and complete before downstream specs reference them.
+
+This review should happen before any spec documents are created or updated, since specs will reference ADR numbers.
+
+## Acceptance Criteria
+
+- [ ] All 9 ADRs (026-034) are written and follow the established format
+- [ ] ADRs cross-reference each other correctly (e.g., ADR-028 references ADR-029, ADR-027 references ADR-029)
+- [ ] No ADR contradicts another (e.g., ADR-026's Interface trait must be compatible with ADR-033's OperationEnv)
+- [ ] Crate dependency graph from ADR-027 is acyclic (core depends on nothing heavy)
+- [ ] Layer boundaries from ADR-026 cleanly separate Transport, Interface, and Protocol
+- [ ] OperationEnv dispatch model from ADR-033 is consistent with ADR-028 (auth service) and ADR-027 (crate decomposition)
+- [ ] Terminology is consistent (head/worker everywhere per ADR-034)
+- [ ] Open questions referenced in ADRs have proposed resolutions consistent with the decision
+- [ ] Each ADR has clear consequences (both positive and negative)
+- [ ] ADRs are added to the README.md ADR table
+
+## References
+
+- docs/architecture/decisions/ — all existing ADRs 001-025 for format reference
+- docs/research/integration-plan.md — Phase 0 review checklist
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion