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/openai-codex/.github/workflows/blob-size-policy.yml

@@ -0,0 +1,34 @@
+name: blob-size-policy
+
+on:
+  pull_request: {}
+
+jobs:
+  check:
+    name: Blob size policy
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Determine PR comparison range
+        id: range
+        shell: bash
+        run: |
+          set -euo pipefail
+          echo "base=${{ github.event.pull_request.base.sha }}" >> "$GITHUB_OUTPUT"
+          echo "head=${{ github.event.pull_request.head.sha }}" >> "$GITHUB_OUTPUT"
+
+      - name: Check changed blob sizes
+        env:
+          BASE_SHA: ${{ steps.range.outputs.base }}
+          HEAD_SHA: ${{ steps.range.outputs.head }}
+        run: |
+          python3 scripts/check_blob_size.py \
+            --base "$BASE_SHA" \
+            --head "$HEAD_SHA" \
+            --max-bytes 512000 \
+            --allowlist .github/blob-size-allowlist.txt