Add Feedback domain module: public submission flow, admin CRUD, reporting

New /feedback API domain backed by its own FEEDBACK_DB, mirroring the
Calendar domain's router -> service -> DB pool layering:

- Public endpoints (no auth): eligible-events listing, event config,
  submission with honeypot + rate limiting (in-memory + DB backstop).
- Admin endpoints (session-header auth, reusing Calendar's users/sessions
  via a swappable feedback.auth.ts boundary): events/songs/questions CRUD,
  bulk reorder/assignment, aggregated reporting, CSV export.
- Schema in sql/feedback/001_init.sql (8 tables), applied and verified
  against the real FEEDBACK_DB.
- 64 Jest tests covering validation, auth, rate limiting, CSV escaping,
  and report aggregation (pure functions, no DB needed).

Includes fixes from a security review: path traversal defense doesn't
apply here (that's the frontend proxy, separate repo), but the
rate-limiter cluster does - recordSubmission now counts every processed
request (not just successful ones), the in-memory Map evicts empty
entries instead of growing unbounded, FEEDBACK_IP_SALT is required at
boot instead of silently degrading to unsalted hashing, and submission
answer/rating arrays are capped and de-duplicated to bound insert
amplification.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/feedback/feedback.auth.test.ts

@@ -0,0 +1,87 @@
+import {Request, Response} from 'express';
+
+jest.mock('../../src/models/calendar/users/users.service', () => ({
+	checkSession: jest.fn()
+}));
+
+import * as UserService from '../../src/models/calendar/users/users.service';
+import {requireAdminAuth, sessionHeaderAuthenticator} from '../../src/models/feedback/feedback.auth';
+
+const mockCheckSession = UserService.checkSession as jest.Mock;
+
+const makeReq = (headers: Record<string, string>): Request => {
+	return {
+		header: (name: string) => headers[name],
+		ip: '203.0.113.42'
+	} as unknown as Request;
+};
+
+const makeRes = (): Response => {
+	const res: any = {};
+	res.status = jest.fn().mockReturnValue(res);
+	res.send = jest.fn().mockReturnValue(res);
+	res.locals = {};
+	return res as Response;
+};
+
+describe('sessionHeaderAuthenticator', () => {
+	beforeEach(() => mockCheckSession.mockReset());
+
+	it('returns null when headers are missing', async () => {
+		const identity = await sessionHeaderAuthenticator(makeReq({}));
+		expect(identity).toBeNull();
+		expect(mockCheckSession).not.toHaveBeenCalled();
+	});
+
+	it('returns null when checkSession finds no user', async () => {
+		mockCheckSession.mockResolvedValue(null);
+		const identity = await sessionHeaderAuthenticator(makeReq({'X-Session-Id': '1', 'X-Session-Key': 'k'}));
+		expect(identity).toBeNull();
+	});
+
+	it('returns null for a valid session on an inactive account', async () => {
+		mockCheckSession.mockResolvedValue({userId: 1, email: 'a@nachklang.art', fullName: 'A', isActive: false});
+		const identity = await sessionHeaderAuthenticator(makeReq({'X-Session-Id': '1', 'X-Session-Key': 'k'}));
+		expect(identity).toBeNull();
+	});
+
+	it('returns the identity for a valid session on an active account', async () => {
+		mockCheckSession.mockResolvedValue({userId: 1, email: 'a@nachklang.art', fullName: 'Anna Admin', isActive: true});
+		const identity = await sessionHeaderAuthenticator(makeReq({'X-Session-Id': '1', 'X-Session-Key': 'k'}));
+		expect(identity).toEqual({id: '1', email: 'a@nachklang.art', displayName: 'Anna Admin'});
+	});
+
+	it('passes the session id and key from headers through to checkSession, never from query params', async () => {
+		mockCheckSession.mockResolvedValue({userId: 1, email: 'a@nachklang.art', fullName: 'A', isActive: true});
+		await sessionHeaderAuthenticator(makeReq({'X-Session-Id': '42', 'X-Session-Key': 'sekret'}));
+		expect(mockCheckSession).toHaveBeenCalledWith('42', 'sekret', '203.0.113.42');
+	});
+});
+
+describe('requireAdminAuth', () => {
+	beforeEach(() => mockCheckSession.mockReset());
+
+	it('responds 401 and does not call next() when unauthenticated', async () => {
+		mockCheckSession.mockResolvedValue(null);
+		const req = makeReq({});
+		const res = makeRes();
+		const next = jest.fn();
+
+		await requireAdminAuth(req, res, next);
+
+		expect(res.status).toHaveBeenCalledWith(401);
+		expect(next).not.toHaveBeenCalled();
+	});
+
+	it('sets res.locals.admin and calls next() when authenticated', async () => {
+		mockCheckSession.mockResolvedValue({userId: 1, email: 'a@nachklang.art', fullName: 'Anna Admin', isActive: true});
+		const req = makeReq({'X-Session-Id': '1', 'X-Session-Key': 'k'});
+		const res = makeRes();
+		const next = jest.fn();
+
+		await requireAdminAuth(req, res, next);
+
+		expect(next).toHaveBeenCalled();
+		expect(res.locals.admin).toEqual({id: '1', email: 'a@nachklang.art', displayName: 'Anna Admin'});
+	});
+});