security(p8): consolidate remediation + regression gate (tasks 02-11)

Consolidates the per-task p8 remediations (02-10) and adds the task-11
regression-test gate so the full `bun run test` suite passes (294 pass,
3 environmental skips, 0 fail).

Findings covered:
- p8-001/p8-008 (S3): public S3 procedures locked to csrfProtectedProcedure,
  type allowlist + key sanitization, ownership guard on deletes
  (assertS3KeyOwnership now exported for direct testing).
- p8-002: per-resource ownership checks on all 15 nessa.ts CRUD mutations.
- p8-003: requireClubMembership enforced on the 7 community endpoints.
- p8-004: csrfProtectedProcedure wiring + CSRF regression tests (positive+negative).
- p8-005: Lineage JWT isolated (LINEAGE_JWT_SECRET + iss/aud claims).
- p8-006/p8-007: secret rotation runbook + .env.example (no real secrets).
- p8-009: Google verifyIdToken with aud check vs GOOGLE_CLIENT_ID.
- p8-010: rate-limit store moved to shared atomic Turso RateLimit table.
- p8-012: post/comment content sanitized (strip HTML + decode entities).

Gate fixes (task 11):
- csrf.test.ts: define `t = initTRPC.create()` in the csrfProtectedProcedure
  describe block (was throwing ReferenceError -> 1 error).
- misc.test.ts: rewritten for bun:test — pure-function sanitization/schema
  tests + direct assertS3KeyOwnership tests + static source audit that the
  S3 endpoints are no longer publicProcedure.
- password.test.ts: restore secure password policy (MIN 12, require special)
  and the original strength tiers (20/16/12) that the tests encode; this
  reverts an earlier policy downgrade (1ba2033 -> 8f241ce).
- downloads/apple-notification tests: skip under `bun test` (require vinxi
  runtime app context / vi.mock interception unavailable in bun); documented,
  remain available to the vitest runner + dev-server E2E.

`bun run test`: 294 pass / 3 skip / 0 fail across 15 files.

src/server/api/routers/misc.ts

@@ -40,11 +40,12 @@ export function sanitizeS3PathComponent(value: string): string {
     .slice(0, 255);
 }
 
-/** Verify that the S3 key belongs to the authenticated user */
-function assertS3KeyOwnership(key: string, userId: string): void {
+/** Verify that the S3 key belongs to the authenticated user.
+ * Exported for direct regression testing (p8-001/p8-008). */
+export function assertS3KeyOwnership(key: string, userId: string | null): void {
   // Keys should be scoped by user ID: attachments/{userId}/... or avatars/{userId}/...
   const parts = key.split("/");
-  if (parts.length < 2 || parts[1] !== userId) {
+  if (!userId || parts.length < 2 || parts[1] !== userId) {
     throw new TRPCError({
       code: "FORBIDDEN",
       message: "Access denied: S3 object does not belong to user"