fix(auth): stop the address-bar mirror eating emailed auth tokens, and unlock revoked accounts

Two independent bugs made an email+password registration unrecoverable in prod.

The verification link did nothing. urlWithParams/clearParams rebuilt the URL as
pathname+query and dropped the fragment — but the one-time auth tokens ride the
fragment (#verify=/#reset=, SB3), and the providers that mirror nav params
(useUrlMirror in FeedFilters/Playlists/Plex/Channels) sit ABOVE the lazily-loaded
<App> in main.tsx. Their mount effect replaceState'd the token away before the auth
card's chunk had loaded, so the card read an empty hash: the link opened a bare
sign-in page, no request, no banner. Both helpers now carry the fragment over.

The account was then locked out for good. SEC-10 nulls password_hash when an
unverified account is attested (here: admin approval landing before the user could
verify — which the bug above made impossible). That is indistinguishable from a
Google-only account, and reset eligibility keyed off password_hash alone, so no
reset link was ever issued: no password to sign in with, and no way to get one.
users.password_revoked_at records the revocation, reset eligibility honours it, and
setting a password again (reset-confirm or set-password) clears it. An account that
never had a password stays ineligible on purpose — its owner adds one from Settings.

/auth/verify now also answers password_reset_required so the card can say why the
registered password stopped working, instead of leaving the user at the uniform
"Invalid email or password". Telling the holder of a valid verify token leaks
nothing: they have already proved they own the mailbox.

The 0078 migration backfills the stamp for rows carrying the exact lockout signature
(local, non-demo, no password, unverified), so existing victims recover unaided.

backend/tests/test_auth_session.py

@@ -341,3 +341,134 @@ def test_register_route_is_refused_when_registration_is_closed(client, db, monke
         db.execute(_select(User).where(User.email == "closed@example.com")).scalar_one_or_none()
         is None
     )
+
+
+# --- SEC-10 lockout: a revoked preset password must stay RECOVERABLE ---------------------------
+#
+# Regression pack for the prod incident of 2026-09-02. An account registered with a password, then
+# approved by an admin BEFORE its email was verified, ended up with password_hash = NULL. That is
+# also what a Google-only account looks like, and reset eligibility keyed off `password_hash` alone —
+# so the account could neither sign in (no password) nor obtain a reset link, and every response on
+# the way was a deliberately uniform "ok"/401. `password_revoked_at` is the trace that tells the two
+# apart; these pin each step of the way back in.
+
+
+def _capture_reset_links(monkeypatch) -> list[str]:
+    """Patch the reset mailer and collect the recipients it is asked to write to."""
+    from app.routes import auth as auth_mod
+
+    sent: list[str] = []
+    monkeypatch.setattr(auth_mod.email_mod, "send_password_reset", lambda to, link: sent.append(to))
+    return sent
+
+
+def test_the_approval_revoke_stamps_password_revoked_at(db, make_user):
+    from app.routes.admin import _activate_user_by_email
+
+    victim = make_user(
+        email="stamped@example.com",
+        password="attacker-chosen",
+        email_verified=False,
+        is_active=False,
+    )
+    assert victim.password_revoked_at is None
+
+    _activate_user_by_email(db, "stamped@example.com")
+
+    assert victim.password_hash is None
+    assert victim.password_revoked_at is not None  # …so the reset flow can tell it HAD a password
+
+
+def test_an_account_whose_password_was_revoked_can_still_get_a_reset_link(
+    db, make_user, monkeypatch
+):
+    # THE lockout bug: without the stamp this sent nothing, and the account was unrecoverable.
+    from app.routes.admin import _activate_user_by_email
+    from app.routes.auth import _send_reset_if_eligible
+
+    make_user(
+        email="lockedout@example.com",
+        password="chosen at registration",
+        email_verified=False,
+        is_active=False,
+    )
+    _activate_user_by_email(db, "lockedout@example.com")
+    sent = _capture_reset_links(monkeypatch)
+
+    _send_reset_if_eligible("lockedout@example.com")
+
+    assert sent == ["lockedout@example.com"]
+
+
+def test_a_google_only_account_is_still_not_reset_eligible(db, make_user, monkeypatch):
+    # The other side of the rule: an account that NEVER had a password gets no reset link — its owner
+    # adds one from Settings while signed in (/auth/set-password), which proves identity by session.
+    from app.routes.auth import _send_reset_if_eligible
+
+    make_user(email="googler@example.com", password=None, google_sub="sub-123")
+    sent = _capture_reset_links(monkeypatch)
+
+    _send_reset_if_eligible("googler@example.com")
+
+    assert sent == []
+
+
+def test_completing_a_reset_clears_the_revocation_stamp(client, db, make_user):
+    from app.routes.admin import _activate_user_by_email
+    from app.routes.auth import _issue_token
+
+    user = make_user(
+        email="recovered@example.com",
+        password="chosen at registration",
+        email_verified=False,
+        is_active=False,
+    )
+    _activate_user_by_email(db, "recovered@example.com")
+    raw = _issue_token(db, user, "reset", timedelta(hours=1))
+    db.commit()
+
+    ok = client.post(
+        "/auth/password-reset/confirm", json={"token": raw, "password": "a brand new one"}
+    )
+
+    assert ok.status_code == 200
+    db.expire_all()
+    assert user.password_hash is not None
+    assert user.password_revoked_at is None  # spent — not a permanently reset-eligible account
+    assert _login(client, "recovered@example.com", "a brand new one").status_code == 200
+
+
+def test_verify_tells_a_revoked_account_that_it_needs_a_new_password(client, db, make_user):
+    # The banner's input. Saying so leaks nothing: the caller just proved mailbox control by holding a
+    # valid single-use verify token. Without it the user meets only the uniform "Invalid email or
+    # password" and has no way to learn why the password they chose stopped working.
+    from app.routes.admin import _activate_user_by_email
+    from app.routes.auth import _issue_token
+
+    user = make_user(
+        email="needspw@example.com",
+        password="chosen at registration",
+        email_verified=False,
+        is_active=False,
+    )
+    _activate_user_by_email(db, "needspw@example.com")
+    raw = _issue_token(db, user, "verify", timedelta(hours=1))
+    db.commit()
+
+    r = client.post("/auth/verify", json={"token": raw})
+
+    assert r.status_code == 200
+    assert r.json() == {"ok": True, "password_reset_required": True}
+
+
+def test_verify_reports_no_reset_needed_for_an_intact_account(client, db, make_user):
+    from app.routes.auth import _issue_token
+
+    user = make_user(email="intact@example.com", email_verified=False, is_active=False)
+    raw = _issue_token(db, user, "verify", timedelta(hours=1))
+    db.commit()
+
+    r = client.post("/auth/verify", json={"token": raw})
+
+    assert r.status_code == 200
+    assert r.json() == {"ok": True, "password_reset_required": False}