Implement Issue #1: User Accounts & Profiles

- Admin-only account creation (no self-registration); invite-token flow
  replaces the public /auth/register endpoint
- New volunteer fields: phone, is_trainee, operational_roles,
  notification_preference, admin_notes, last_login, completed_shifts
- Role-scoped profile editing: volunteers update name/phone only;
  admins update all fields including notes and trainee flag
- /auth/activate endpoint for invite-token-based account activation
- /api/v1/volunteers/{id}/invite for admin to resend invite links
- last_login recorded on each successful authentication

Tests:
- Go: handler tests (auth rules, create, activate, update scoping) via
  Storer/AuthServicer interfaces and fake store; auth unit tests for
  HashPassword, IssueToken, and Parse
- Frontend: RTL tests for Activate, Profile, and Volunteers pages
- Fixed CRA 5 + React Router v7 Jest compatibility (moduleNameMapper +
  TextEncoder polyfill)
- Replaced stale CRA App.test.tsx placeholder with real tests

CI:
- .gitea/workflows/ci.yml runs go vet, go test, tsc, and npm test on
  every push and pull request

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

.gitea/workflows/ci.yml

@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  go:
+    name: Go tests & lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache: true
+
+      - name: go vet
+        run: go vet ./...
+
+      - name: go test
+        run: go test ./...
+
+  web:
+    name: Frontend tests & type-check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+          cache: npm
+          cache-dependency-path: web/package-lock.json
+
+      - name: Install dependencies
+        working-directory: web
+        run: npm ci
+
+      - name: Type check
+        working-directory: web
+        run: npx tsc --noEmit
+
+      - name: Run tests
+        working-directory: web
+        run: CI=true npm test -- --watchAll=false