chore: Manage Composer dependencies with Dependabot

Add a composer ecosystem to dependabot.yml so runtime and development
dependencies are kept current, using a chore prefix for development
updates so they do not cut a release.

Remove renovate.json, which used the deprecated config:base preset and
overlapped with Dependabot.

Guard the automerge close job so it only closes dependency pull requests
that touch the npm manifests. Without it a Composer update, which never
changes src/**, would be closed automatically.

Set CODEOWNERS to the sdk team to match the other SDK repositories.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RFK47311nWtbd3gHmjdknR

Author: claude

.github/CODEOWNERS

@@ -1 +1 @@
-* @rchodava @andrii-balitskyi @seveibar
+* @seamapi/sdk

.github/dependabot.yml

@@ -21,3 +21,15 @@ updates:
         update-types:
           - patch
           - minor
+  - package-ecosystem: composer
+    directory: '/'
+    schedule:
+      interval: daily
+    commit-message:
+      prefix: feat
+      prefix-development: chore
+      include: scope
+    ignore:
+      - dependency-name: '*'
+        update-types:
+          - 'version-update:semver-major'

.github/workflows/automerge.yml

@@ -16,6 +16,7 @@ jobs:
       checks: read
     outputs:
       has_changes: ${{ steps.changed.outputs.any_changed == 'true' }}
+      is_npm_update: ${{ steps.npm.outputs.any_changed == 'true' }}
       is_generation_successful: ${{ steps.checks.outputs.conclusion == 'success' }}
     steps:
       - name: Wait for checks
@@ -31,6 +32,13 @@ jobs:
         with:
           files: |
             src/**
+      - name: Get changed npm manifests
+        id: npm
+        uses: tj-actions/changed-files@v44
+        with:
+          files: |
+            package.json
+            package-lock.json
   merge:
     name: Merge
     runs-on: ubuntu-latest
@@ -53,7 +61,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     needs: changes
-    if: needs.changes.outputs.has_changes == 'false' && needs.changes.outputs.is_generation_successful == 'true'
+    if: needs.changes.outputs.has_changes == 'false' && needs.changes.outputs.is_generation_successful == 'true' && needs.changes.outputs.is_npm_update == 'true'
     steps:
       - name: Close pull request
         run: gh pr close "$PR_URL"