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/actions/setup-rusty-v8/action.yml

@@ -0,0 +1,42 @@
+name: setup-rusty-v8
+description: Download and verify Codex-built rusty_v8 artifacts for Cargo builds.
+inputs:
+  target:
+    description: Rust target triple with Codex-built V8 release artifacts.
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Configure rusty_v8 artifact overrides and verify checksums
+      shell: bash
+      env:
+        TARGET: ${{ inputs.target }}
+      run: |
+        set -euo pipefail
+
+        version="$(python3 "${GITHUB_WORKSPACE}/.github/scripts/rusty_v8_bazel.py" resolved-v8-crate-version)"
+        release_tag="rusty-v8-v${version}"
+        base_url="https://github.com/openai/codex/releases/download/${release_tag}"
+        binding_dir="${RUNNER_TEMP}/rusty_v8"
+        archive_path="${binding_dir}/librusty_v8_release_${TARGET}.a.gz"
+        binding_path="${binding_dir}/src_binding_release_${TARGET}.rs"
+        checksums_path="${binding_dir}/rusty_v8_release_${TARGET}.sha256"
+
+        mkdir -p "${binding_dir}"
+        curl -fsSL "${base_url}/librusty_v8_release_${TARGET}.a.gz" -o "${archive_path}"
+        curl -fsSL "${base_url}/src_binding_release_${TARGET}.rs" -o "${binding_path}"
+        curl -fsSL "${base_url}/rusty_v8_release_${TARGET}.sha256" -o "${checksums_path}"
+
+        if [[ "$(wc -l < "${checksums_path}")" -ne 2 ]]; then
+          echo "Expected exactly two checksums for ${TARGET} in ${checksums_path}" >&2
+          exit 1
+        fi
+
+        if command -v sha256sum >/dev/null 2>&1; then
+          (cd "${binding_dir}" && sha256sum -c "${checksums_path}")
+        else
+          (cd "${binding_dir}" && shasum -a 256 -c "${checksums_path}")
+        fi
+        echo "RUSTY_V8_ARCHIVE=${archive_path}" >> "${GITHUB_ENV}"
+        echo "RUSTY_V8_SRC_BINDING_PATH=${binding_path}" >> "${GITHUB_ENV}"