Add ambient-action workflow for issue comment automation

Triggers an ACP session when org members comment @ambient on issues.
Restricted to OWNER and MEMBER author associations for security.
Workflow token scoped to contents: read per least-privilege principle.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jeremyeder

.github/workflows/ambient.yml

@@ -0,0 +1,25 @@
+name: Ambient
+
+on:
+  issue_comment:
+    types: [created]
+
+permissions:
+  contents: read
+
+jobs:
+  ambient:
+    if: >-
+      startsWith(github.event.comment.body, '@ambient') &&
+      contains(fromJSON('["OWNER","MEMBER"]'), github.event.comment.author_association)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: ambient-code/ambient-action@v2
+        with:
+          api-url: ${{ secrets.AMBIENT_API_URL }}
+          api-token: ${{ secrets.AMBIENT_BOT_TOKEN }}
+          project: gps-ambient-action
+          prompt: ${{ github.event.comment.body }}
+          display-name: "Issue #${{ github.event.issue.number }}"
+          repos: '[{"url": "https://github.com/${{ github.repository }}", "branch": "main", "autoPush": true}]'
+          labels: '{"source": "github-issue", "issue": "${{ github.event.issue.number }}"}'