ci: integrate timvw-ci-bot GitHub App for workflow triggers

Update CI workflow to use GitHub App authentication instead of default
GITHUB_TOKEN. This ensures workflows are triggered when PRs are created
by bots like Renovate.

Changes:
- Add token generation step using actions/create-github-app-token@v1
- Configure checkout action to use generated app token
- Apply to all jobs: test, build, lint, cross-compile

The BOT_APP_ID and BOT_PRIVATE_KEY secrets must be configured in the
repository settings for this to work.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: timvw

.github/workflows/ci.yml

@@ -15,8 +15,17 @@ jobs:
         go-version: ['1.21', '1.22', '1.23']
 
     steps:
+      - name: Generate GitHub App token
+        id: generate-token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.BOT_APP_ID }}
+          private-key: ${{ secrets.BOT_PRIVATE_KEY }}
+
       - name: Checkout code
         uses: actions/checkout@v4
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Set up Go
         uses: actions/setup-go@v5
@@ -44,8 +53,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Generate GitHub App token
+        id: generate-token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.BOT_APP_ID }}
+          private-key: ${{ secrets.BOT_PRIVATE_KEY }}
+
       - name: Checkout code
         uses: actions/checkout@v4
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Set up Go
         uses: actions/setup-go@v5
@@ -70,8 +88,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Generate GitHub App token
+        id: generate-token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.BOT_APP_ID }}
+          private-key: ${{ secrets.BOT_PRIVATE_KEY }}
+
       - name: Checkout code
         uses: actions/checkout@v4
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Set up Go
         uses: actions/setup-go@v5
@@ -88,8 +115,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Generate GitHub App token
+        id: generate-token
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.BOT_APP_ID }}
+          private-key: ${{ secrets.BOT_PRIVATE_KEY }}
+
       - name: Checkout code
         uses: actions/checkout@v4
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Set up Go
         uses: actions/setup-go@v5