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

reference/asciinema-3.2.0/.github/workflows/ci.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches: ["develop"]
+  pull_request:
+    branches: ["develop"]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        rust: [default, msrv]
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Install Nix
+        uses: nixbuild/nix-quick-install-action@v34
+
+      - name: Setup Nix cache
+        uses: nix-community/cache-nix-action@v6
+        with:
+          primary-key: nix-${{ runner.os }}-${{ matrix.rust }}-${{ hashFiles('**/*.nix', '**/flake.lock') }}
+          restore-prefixes-first-match: nix-${{ runner.os }}-${{ matrix.rust }}-
+
+      - name: Build
+        run: nix develop .#${{ matrix.rust }} --command cargo build --verbose
+
+      - name: Run cargo tests
+        run: nix develop .#${{ matrix.rust }} --command cargo test --verbose
+
+      - name: Run integration tests
+        run: nix develop .#${{ matrix.rust }} --command tests/integration.sh
+
+      - name: Check formatting
+        run: nix develop .#${{ matrix.rust }} --command cargo fmt --check
+
+      - name: Lint with clippy
+        run: nix develop .#${{ matrix.rust }} --command cargo clippy