chore(deps): consolidate dependency automation on Renovate + enable CI for merge queue (#765)

* ci: run CI on merge_group for merge queue support

Add the merge_group trigger so the workflow executes on the temporary
commits GitHub creates for the merge queue (gh-readonly-queue/**). Without
it, the required status check never runs and the queue stalls.

Disable cancel-in-progress for merge_group events: cancelling a run that
is in the queue fails the group, so only cancel duplicate push/PR runs.

* chore(deps): remove dependabot in favor of renovate

Dependabot and Renovate were both opening PRs for the same dependencies
(e.g. codecov-action #648/#740, @biomejs/biome #763/#701, vitest #587/#756).
Keep Renovate only: it already groups ecosystem updates, schedules major
reviews, and auto-merges safe patches.

Delete the dependabot config and its auto-merge workflow (gated on
dependabot[bot] actor), and reword the type:dependency label.

* chore(deps): expand renovate grouping for real dependency map

Group the remaining ecosystems by the actual dependencies in
gradle/libs.versions.toml and the frontend package.json files:

- Spring Framework & Security, Spring AI, Jackson (tools.jackson + 2.x compat),
  Reactor, backend testing libs, Gradle plugins
- Vue UI/headless stack (reka-ui, shadcn-vue, vaul-vue, embla-carousel-vue,
  tanstack-vue-table, pragmatic-drag-and-drop, etc.)
- Vite/Vitest tooling, TypeScript and @types, @vue/* and @vueuse/*, Astro
  icon sets, Playwright/axe coverage

Drop the stale matchFileNames from Vue Core and Astro so grouping applies
across app, admin and marketing, and add groups that were missing entirely.

Author: yacosta738

.github/dependabot.yml

@@ -28,7 +28,7 @@
 
 - name: "type:dependency"
   color: "e3e3e3"
-  description: "Dependency updates (Dependabot or manual)"
+  description: "Dependency updates (Renovate or manual)"
 
 - name: "type:security"
   color: "d93f0b"

.github/labels.yml

@@ -5,10 +5,12 @@ on:
     branches: [main, develop]
   pull_request:
     branches: [main, develop]
+  merge_group:
+    branches: [main]
 
 concurrency:
-  group: ci-${{ github.ref }}
-  cancel-in-progress: true
+  group: ci-${{ github.workflow }}-${{ github.event_name }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name != 'merge_group' }}
 
 permissions:
   contents: read