M1 security: close the password backdoor, apply re-review, pin E.164

Acts on an adversarial review of the M1 auth and authorization code.
Five findings fixed; the rest recorded in SECURITY-FINDINGS.md as the
M1 exit criteria rather than left in a tool transcript.

- auth: serve /phone-number/request-password-reset, /phone-number/
  reset-password and /sign-in/phone-number as 404. better-auth's
  phoneNumber() registers all three unconditionally -- they are NOT
  gated on emailAndPassword.enabled:false. Left live they form a
  silent second credential path: request-password-reset stores an OTP
  and sends no SMS (sendPasswordResetOTP was never configured, so the
  owner is never told), reset-password mints a bcrypt credential row,
  and sign-in/phone-number then accepts it forever with no OTP. The
  OTP gate still applies, so this is not remote unauthenticated
  takeover -- it converts one momentary OTP compromise into permanent
  access the victim cannot see or rotate.

- auth: drop bearer(). It accepts the plaintext sessions.token column
  as an Authorization credential, making any single leaked row a
  replayable login. The mobile client it was added for is hypothetical.

- auth: pin E.164 via phoneNumberValidator, and add toE164/isE164 to
  @linkder/shared. phone is UNIQUE and bans are per-account, so
  "+34600111222" and "0034600111222" being separately storable meant
  one handset could hold two accounts and a ban was escapable by
  retyping. 15 tests.

- auth: NEXT_PUBLIC_APP_URL now throws in production instead of
  falling back to localhost, which was silently dropping Secure and
  the __Secure- prefix from the production session cookie.

- pro.upsertProfile: actually apply requiresReReview. It was computed,
  returned to the client and never acted on, so a verified plumber
  could become a verified electrician in another city by ignoring a
  response flag. Now demotes to pending in the same transaction and
  audits it. Trade changes count as material (they did not before) --
  the licence is per-trade. Needed a verified -> pending edge in
  VERIFICATION_GRAPH, which did not exist.

Removed two untracked scratch repro files. The impersonation repro
depended on bearer() for transport and no longer applies as written;
the underlying finding (resolveSession drops impersonatedBy, so admin
actions are audited as the victim) is open and documented.

typecheck, lint, build clean; 127 tests pass.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/shared/src/state-machines.ts

@@ -99,7 +99,11 @@ const PAYMENT_GRAPH: Graph<PaymentStatus> = {
 const VERIFICATION_GRAPH: Graph<VerificationStatus> = {
   draft: ['pending'],
   pending: ['verified', 'rejected'],
-  verified: ['suspended'],
+  // 'pending' is reachable from 'verified' because a material profile edit
+  // (trade, base location, service radius) sends a live pro back for re-review.
+  // Without this edge the re-review in pro.upsertProfile is not representable
+  // and a verified plumber could silently become a verified electrician.
+  verified: ['suspended', 'pending'],
   rejected: ['pending'],
   suspended: ['verified', 'rejected'],
 };