Adds Gemini CLI to Github Actions (#2718)

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I have added sample code updates to the [changelog].
- [x] I updated/added relevant documentation (doc comments with `///`).

.github/workflows/gemini-issue-scheduled-triage.yml

@@ -0,0 +1,123 @@
+name: '📋 Gemini Scheduled Issue Triage'
+
+on:
+  schedule:
+    - cron: '0 * * * *' # Runs every hour
+  workflow_dispatch:
+
+concurrency:
+  group: '${{ github.workflow }}'
+  cancel-in-progress: true
+
+defaults:
+  run:
+    shell: 'bash'
+
+permissions:
+  contents: 'read'
+  id-token: 'write'
+  issues: 'write'
+  statuses: 'write'
+
+jobs:
+  triage-issues:
+    timeout-minutes: 5
+    runs-on: 'ubuntu-latest'
+
+    steps:
+      - name: 'Checkout repository'
+        uses: 'actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683' # ratchet:actions/checkout@v4
+
+      - name: 'Generate GitHub App Token'
+        id: 'generate_token'
+        if: |-
+          ${{ vars.APP_ID }}
+        uses: 'actions/create-github-app-token@df432ceedc7162793a195dd1713ff69aefc7379e' # ratchet:actions/create-github-app-token@v2
+        with:
+          app-id: '${{ vars.APP_ID }}'
+          private-key: '${{ secrets.APP_PRIVATE_KEY }}'
+
+      - name: 'Find untriaged issues'
+        id: 'find_issues'
+        env:
+          GITHUB_TOKEN: '${{ steps.generate_token.outputs.token || secrets.GITHUB_TOKEN }}'
+          GITHUB_REPOSITORY: '${{ github.repository }}'
+          GITHUB_OUTPUT: '${{ github.output }}'
+        run: |-
+          set -euo pipefail
+
+          echo '🔍 Finding issues without labels...'
+          NO_LABEL_ISSUES="$(gh issue list --repo "${GITHUB_REPOSITORY}" \
+            --search 'is:open is:issue no:label' --json number,title,body)"
+
+          echo '🏷️ Finding issues that need triage...'
+          NEED_TRIAGE_ISSUES="$(gh issue list --repo "${GITHUB_REPOSITORY}" \
+            --search 'is:open is:issue label:"status/needs-triage"' --json number,title,body)"
+
+          echo '🔄 Merging and deduplicating issues...'
+          ISSUES="$(echo "${NO_LABEL_ISSUES}" "${NEED_TRIAGE_ISSUES}" | jq -c -s 'add | unique_by(.number)')"
+
+          echo '📝 Setting output for GitHub Actions...'
+          echo "issues_to_triage=${ISSUES}" >> "${GITHUB_OUTPUT}"
+
+          ISSUE_COUNT="$(echo "${ISSUES}" | jq 'length')"
+          echo "✅ Found ${ISSUE_COUNT} issues to triage! 🎯"
+
+      - name: 'Run Gemini Issue Triage'
+        if: |-
+          ${{ steps.find_issues.outputs.issues_to_triage != '[]' }}
+        uses: 'google-github-actions/run-gemini-cli@v0'
+        id: 'gemini_issue_triage'
+        env:
+          GITHUB_TOKEN: '${{ steps.generate_token.outputs.token || secrets.GITHUB_TOKEN }}'
+          ISSUES_TO_TRIAGE: '${{ steps.find_issues.outputs.issues_to_triage }}'
+          REPOSITORY: '${{ github.repository }}'
+        with:
+          gemini_cli_version: '${{ vars.GEMINI_CLI_VERSION }}'
+          gcp_workload_identity_provider: '${{ vars.GCP_WIF_PROVIDER }}'
+          gcp_project_id: '${{ vars.GOOGLE_CLOUD_PROJECT }}'
+          gcp_location: '${{ vars.GOOGLE_CLOUD_LOCATION }}'
+          gcp_service_account: '${{ vars.SERVICE_ACCOUNT_EMAIL }}'
+          gemini_api_key: '${{ secrets.GEMINI_API_KEY }}'
+          use_vertex_ai: '${{ vars.GOOGLE_GENAI_USE_VERTEXAI }}'
+          use_gemini_code_assist: '${{ vars.GOOGLE_GENAI_USE_GCA }}'
+          settings: |-
+            {
+              "maxSessionTurns": 25,
+              "coreTools": [
+                "run_shell_command(echo)",
+                "run_shell_command(gh label list)",
+                "run_shell_command(gh issue edit)",
+                "run_shell_command(gh issue list)"
+              ],
+              "telemetry": {
+                "enabled": false,
+                "target": "gcp"
+              }
+            }
+          prompt: |-
+            ## Role
+
+            You are an issue triage assistant. Analyze issues and apply
+            appropriate labels. Use the available tools to gather information;
+            do not ask for information to be provided.
+
+            ## Steps
+
+            1. Run: `gh label list`
+            2. Check environment variable: "${ISSUES_TO_TRIAGE}" (JSON array
+               of issues)
+            3. For each issue, apply labels:
+               `gh issue edit "${ISSUE_NUMBER}" --add-label "label1,label2"`.
+               If available, set labels that follow the `kind/*`, `area/*`,
+               and `priority/*` patterns.
+            4. For each issue, if the `status/needs-triage` label is present,
+               remove it using:
+               `gh issue edit "${ISSUE_NUMBER}" --remove-label "status/needs-triage"`
+
+            ## Guidelines
+
+            - Only use existing repository labels
+            - Do not add comments
+            - Triage each issue independently
+            - Reference all shell variables as "${VAR}" (with quotes and braces)