Move CI workflows to repo root .gitea/workflows/ (Gitea requires root location)

- 6 per-product CI workflows with path filters
- P1: Rust (cargo test + clippy + fmt)
- P2: Go agent (go test + vet) + Node SaaS (tsc + npm test)
- P3-P6: Node (npm ci + tsc + npm test)
- Removed old per-product .gitea dirs (Gitea ignores non-root workflows)

.gitea/workflows/ci-p2-drift.yml

@@ -0,0 +1,46 @@
+name: CI — P2 Drift (Go + Node)
+on:
+  push:
+    branches: [main]
+    paths: ['products/02-iac-drift-detection/**']
+  pull_request:
+    paths: ['products/02-iac-drift-detection/**']
+
+jobs:
+  agent:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.22'
+
+      - name: Test agent
+        run: go test ./...
+        working-directory: products/02-iac-drift-detection/agent
+
+      - name: Vet
+        run: go vet ./...
+        working-directory: products/02-iac-drift-detection/agent
+
+  saas:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      - name: Install deps
+        run: npm ci
+        working-directory: products/02-iac-drift-detection/saas
+
+      - name: Type check
+        run: npx tsc --noEmit
+        working-directory: products/02-iac-drift-detection/saas
+
+      - name: Test
+        run: npm test
+        working-directory: products/02-iac-drift-detection/saas