feat(prd-1): implement M3 - Forgejo CI workflows

- ci.yml: 3-job CI (test, prettier, typecheck) on grunt runner
- test-action.yml: agent-mode self-test (weekly + PR path triggers)
- upstream-sync.yml: weekly upstream check with labeled issue dedup
- Updated PRD checkboxes for M3 completion

Progress: 78% complete (7/9 milestones) - M8 (e2e testing) next

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.forgejo/workflows/ci.yml

@@ -0,0 +1,84 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run tests
+        run: bun test
+
+  prettier:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run prettier check
+        run: bun run format:check
+
+  typecheck:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run TypeScript type check
+        run: bun run typecheck