chore: migrate submodule to s2-specs at root and add sync workflow

- Move submodule from s2-internal/src/main/proto to s2-specs at root
- Update s2-internal/build.gradle.kts to use new proto source path
- Add sync_specs.yaml workflow with:
  - peter-evans/create-pull-request@v8
  - sign-commits enabled
  - Listens for s2-specs-update events

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: cristi-

.github/workflows/sync_specs.yaml

@@ -0,0 +1,50 @@
+name: Sync specs submodule
+
+permissions:
+  contents: write
+  pull-requests: write
+
+on:
+  repository_dispatch:
+    types: [s2-specs-update]
+  workflow_dispatch:
+
+jobs:
+  sync-specs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Update submodule
+        id: submodules
+        uses: sgoudham/update-git-submodules@v2.1.1
+        with:
+          submodules: s2-specs
+
+      - name: Setup Java
+        if: ${{ steps.submodules.outputs['s2-specs--updated'] }}
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+
+      - name: Setup Gradle
+        if: ${{ steps.submodules.outputs['s2-specs--updated'] }}
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Regenerate proto files
+        if: ${{ steps.submodules.outputs['s2-specs--updated'] }}
+        run: ./gradlew :s2-internal:generateProto
+
+      - name: Create pull request
+        if: ${{ steps.submodules.outputs['s2-specs--updated'] }}
+        uses: peter-evans/create-pull-request@v8
+        with:
+          committer: s2-helper[bot] <194906454+s2-helper[bot]@users.noreply.github.com>
+          author: s2-helper[bot] <194906454+s2-helper[bot]@users.noreply.github.com>
+          sign-commits: true
+          title: "chore: sync s2-specs submodule"
+          branch: "specs/sync-${{ steps.submodules.outputs['s2-specs--latestShortCommitSha'] }}"
+          body: ${{ steps.submodules.outputs.prBody }}

.gitmodules

@@ -1,3 +1,3 @@
-[submodule "proto"]
-	path = s2-internal/src/main/proto
-	url = https://github.com/s2-streamstore/s2-protos.git
+[submodule "s2-specs"]
+	path = s2-specs
+	url = https://github.com/s2-streamstore/s2-specs.git

s2-internal/build.gradle.kts

@@ -32,6 +32,14 @@ dependencies {
     testRuntimeOnly(libs.junit.platform.launcher)
 }
 
+sourceSets {
+    main {
+        proto {
+            srcDir("../s2-specs/s2")
+        }
+    }
+}
+
 val protobufVersion: String = libs.versions.protobuf.get()
 val grpcVersion: String = libs.versions.grpc.get()
 protobuf {