ci: add GitHub Actions workflow for lint + unit + integration tests

Three parallel jobs on push to main and every PR:
- lint: golangci-lint via golangci-lint-action@v9 (v7+ required for our
  v2 .golangci.yml config; v6 only understands v1 configs)
- test: unit tests with race detector via make test
- test-integration: search-sync-worker integration tests via make
  test-integration SERVICE=search-sync-worker (Docker is pre-installed
  on ubuntu-latest runners, so testcontainers-go can start ES + NATS)

Scoped integration to search-sync-worker only — other services have
their own azure-pipelines.yml and running all -tags=integration tests
in one job would be slow. Expand to a per-service matrix later if
needed.

Also drops goimports from .golangci.yml linters.settings — v2.11+
rejects it (additional properties 'goimports' not allowed) because
goimports was reclassified as a formatter in v2. The duplicate block
under formatters.settings (unchanged) keeps it active with the same
local-prefixes.

https://claude.ai/code/session_01XTmSpmv5dT6UXX7NpRdYqN

Author: claude

.github/workflows/ci.yml

@@ -0,0 +1,69 @@
+name: ci
+
+# Skip CI for docs-only changes. Note: if you later add required status
+# checks, switch to per-job `if:` conditionals since paths-ignore will
+# leave the checks in a "pending" state instead of passing them.
+on:
+  push:
+    branches: [main]
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+  pull_request:
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+
+# Cancel in-progress runs for the same branch when a new commit lands.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+env:
+  GO_VERSION: "1.25.8"
+  # Pin golangci-lint to a known-good version so a new release can't break
+  # CI without a config update. Bump deliberately.
+  GOLANGCI_LINT_VERSION: "v2.11.4"
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+      - uses: golangci/golangci-lint-action@v9
+        with:
+          version: ${{ env.GOLANGCI_LINT_VERSION }}
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+      - name: Unit tests (race detector)
+        run: make test
+
+  # Integration tests run the full testcontainers-go stack (Elasticsearch,
+  # NATS JetStream, MongoDB, Cassandra as applicable per service). Docker is
+  # pre-installed on ubuntu-latest runners. Bump the timeout if container
+  # image pulls are slow on cold cache.
+  test-integration:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+      - name: Integration tests (search-sync-worker)
+        run: make test-integration SERVICE=search-sync-worker

.golangci.yml

@@ -10,9 +10,6 @@ linters:
     - bodyclose
     - exhaustive
   settings:
-    goimports:
-      local-prefixes:
-        - github.com/hmchangw/chat
     exhaustive:
       default-signifies-exhaustive: true
     gocritic: