Initial commit: AirCoding V1.0.0 Alpha architecture baseline

Complete architecture document set with multi-model review remediation:
- Frozen interface contracts, runtime semantics, DB schemas
- Event/tool/error/provider registries
- Scheduler and main agent state machines
- C4 module/code views, solution architecture, baseline V1
- Multi-model review reports and joint assessment
- Phase-gate remediation complete (P0/P1/P2/UX resolved)
- Implementation plan with T-000A through T-045
- Reference folders kept as placeholders only

AirPlan/docs/architecture/adr/ADR-0001-use-airplan-as-the-workflow-root.md

@@ -0,0 +1,15 @@
+# ADR-0001: Use AirPlan As The Workflow Root
+
+- Status: Accepted
+- Date: YYYY-MM-DD
+
+## Context
+This project needs a durable workflow root for planning, execution state, architecture context, validation evidence, and resumable AI sessions.
+
+## Decision
+Store project workflow artifacts under `AirPlan/`, use the repo-root `AGENTS.md` only as a bootstrap shim, and let `aireng` plus `airdo` maintain plan, todo, ADR, and C4 context there.
+
+## Consequences
+- Planning and execution context stay resumable across sessions.
+- Global workflow docs live in one predictable location.
+- Plugin runtime state does not clutter the main project tree.