ci: add smoke-test workflow (#64)

One job that exercises the literal demo/quickstart path with stub
credentials, so 'crashes on import' bugs are caught before judging.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: tcconnally

.github/workflows/smoke-test.yml

@@ -0,0 +1,27 @@
+name: Smoke Test
+
+on:
+  push:
+    branches: [main, ci/smoke-tests]
+  pull_request:
+    branches: [main]
+
+jobs:
+  demo-runs:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - name: Build
+        run: cargo build --locked
+      - name: Smoke test — MCP stdio handshake against a fresh database
+        run: |
+          out=$(printf '%s\n' \
+            '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"smoke","version":"0"}}}' \
+            '{"jsonrpc":"2.0","id":2,"method":"tools/list"}' \
+            | ./target/debug/mimir --db /tmp/smoke.db)
+          echo "$out"
+          echo "$out" | grep -q '"protocolVersion"' || { echo "initialize failed"; exit 1; }
+          echo "$out" | grep -q 'mimir_remember' || { echo "tools/list missing mimir_remember"; exit 1; }