v0.1.0: Performance, incremental indexing, async boundary detection

Performance & quality:
- Transaction wrapping (Querier interface, single tx per index run)
- Composite indexes on edges table for faster traversals
- Cypher WHERE push-down (=, CONTAINS, STARTS WITH → SQL)
- golangci-lint with 25 linters, zero violations
- 11 benchmarks for pipeline, search, and BFS

Incremental indexing:
- Content-hash based file change detection
- Dependency-aware two-level invalidation (changed + dependents)
- Stale file cleanup for deleted files

Async boundary detection:
- Project-wide env var URL scanner (Dockerfile, YAML, .tf, .sh, .env,
  TOML, properties files) with 3-layer secret exclusion
- Env var default extraction in constant propagation (getEnv, os.environ.get,
  process.env with ||/?? fallback)
- ASYNC_CALLS edge type for Cloud Tasks, Pub/Sub, SQS/SNS, RabbitMQ, Kafka
  dispatch patterns, separate from synchronous HTTP_CALLS
- Tool descriptions updated with all edge types

Other improvements:
- Type inference for method dispatch resolution
- Interface implementation detection (IMPLEMENTS edges)
- Improved tool descriptions for discoverability

.github/workflows/release.yml

@@ -12,6 +12,20 @@ permissions:
   contents: write
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.23"
+
+      - uses: golangci/golangci-lint-action@v6
+        with:
+          version: latest
+          args: --timeout=5m
+
   build-unix:
     strategy:
       matrix:
@@ -94,7 +108,7 @@ jobs:
           path: "*.zip"
 
   release:
-    needs: [build-unix, build-windows]
+    needs: [lint, build-unix, build-windows]
     runs-on: ubuntu-latest
     permissions:
       contents: write