fix(plugin): bind adapter to real Hermes gateway API; add contract-test gate

- Resolve the Hermes gateway API lazily via get_adapter_class() so the adapter
  always inherits the real gateway.platforms.base.BasePlatformAdapter instead
  of the ImportError fallback stub (root cause of the AttributeError:
  'set_message_handler' crash at gateway startup).
- Pass Platform('meshtastic') enum to super().__init__ and align
  connect(*, is_reconnect=False) -> bool with the gateway contract.
- Split pure formatting utils into formatting.py; remove the stub fallback.
- Add tests/contract (L0-L3): real-base binding, ABC instantiation, gateway
  run.py wiring replay, signature and event-shape conformance, run against
  hermes-agent pinned to the deployed image source (v2026.8.31).
- Add scripts/contract-test.sh and a contract-test CI job; release publish
  now requires contract tests to pass.
- Untrack stray __pycache__ artifacts.

.gitea/workflows/release.yaml

@@ -8,8 +8,49 @@ on:
       - 'v*'
 
 jobs:
+  # Gateway contract gate: the plugin must bind and wire against the REAL
+  # Hermes gateway API (pinned to the deployed image source) before any
+  # release can be built or published. Without this, adapter/API drift used
+  # to surface only as a gateway crash after deploy (the set_message_handler
+  # AttributeError). HERMES_CONTRACT_REQUIRED=1 turns a missing hermes-agent
+  # into a hard failure so this gate can never silently skip.
+  contract-test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.13 (matches Hermes image)
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+
+      - name: Install uv
+        run: pip install uv
+
+      - name: Clone pinned Hermes gateway source (deployed image tag)
+        run: |
+          git clone --depth 1 --branch v2026.8.31 \
+            https://github.com/NousResearch/hermes-agent.git plugin/.hermes-src
+          test "$(git -C plugin/.hermes-src rev-parse HEAD)" = \
+            "29112bef099274229cadff79cdff7bf7b99c4b77"
+
+      - name: Editable install hermes-agent + pytest
+        run: |
+          uv venv --python 3.13 plugin/.venv-contract
+          uv pip install --python plugin/.venv-contract/bin/python -e plugin/.hermes-src
+          uv pip install --python plugin/.venv-contract/bin/python pytest
+
+      - name: Run gateway contract tests
+        env:
+          HERMES_CONTRACT_REQUIRED: '1'
+        run: |
+          cd plugin
+          .venv-contract/bin/python -m pytest tests/contract -q
+
   test-and-release:
     runs-on: ubuntu-latest
+    needs: contract-test
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -40,13 +81,13 @@ jobs:
           echo "Publishing release for $tag_name"
           wheel_file=$(ls plugin/dist/*.whl | head -n 1)
           tar_file=$(ls plugin/dist/*.tar.gz | head -n 1)
-          
+
           # Create release
           response=$(curl -s -k -X POST "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases" \
             -H "Authorization: token $GITEA_TOKEN" \
             -H "Content-Type: application/json" \
             -d "{\"tag_name\": \"$tag_name\", \"name\": \"$tag_name\", \"body\": \"Release $tag_name for hermes-meshtastic plugin\"}")
-          
+
           release_id=$(echo "$response" | grep -o '"id":[0-9]*' | head -n 1 | cut -d: -f2)
           if [ -n "$release_id" ]; then
             curl -s -k -X POST "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases/$release_id/assets?name=$(basename $wheel_file)" \