Implement M6: functional GUI views, GitHub Actions CI

Wire all remaining dashboard views to real API: agent detail page
with heartbeat status and capabilities, audit trail with time range/
actor/resource filters, notifications with grouped-by-cert view and
read/unread state, policies with severity summary bar, new issuers
and targets list views. Add GitHub Actions CI with parallel Go and
Frontend jobs. Update Makefile with test-cover and frontend-build
targets.

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

.github/workflows/ci.yml

@@ -0,0 +1,63 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  go-build-and-test:
+    name: Go Build & Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: '1.22'
+
+      - name: Go Build
+        run: |
+          go build ./cmd/server/...
+          go build ./cmd/agent/...
+
+      - name: Go Vet
+        run: go vet ./...
+
+      - name: Go Test with Coverage
+        run: |
+          go test ./internal/service/... ./internal/api/handler/... ./internal/integration/... -count=1 -cover -coverprofile=coverage.out
+
+      - name: Upload Coverage Report
+        uses: actions/upload-artifact@v4
+        with:
+          name: go-coverage
+          path: coverage.out
+          retention-days: 30
+
+  frontend-build:
+    name: Frontend Build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      - name: Install Dependencies
+        working-directory: web
+        run: npm ci
+
+      - name: TypeScript Check
+        working-directory: web
+        run: npx tsc --noEmit
+
+      - name: Build Frontend
+        working-directory: web
+        run: npx vite build