feat(auth)!: go fully passwordless and fix cross-check review findings

Remove password authentication everywhere; the only session doors are
passkey (WebAuthn), email OTP, in-game bind codes, QR scan-login, and
op-login vouching. Remediates the 33-finding cross-check review across
backend, CLI, panel, plugins, and docs.

Backend/CLI:
- Drop password routes and fields from account/user/onboard/auth
  handlers; align tests (new account subtests, naming reserves
  "console", op-login/onboard/qr-login test updates).
- Add migrations 0016_op_login.sql and 0017_drop_password.sql.
- Thread panel/admin hostnames from hostcfg through api.go,
  setup_panel.go, tui_root.go and tui_preflight.go instead of
  hardcoding; bootstrap.sh writes panel-hostname/admin-hostname
  into felis.toml.
- Reword breakglass and TUI copy for passwordless flows.

Panel:
- Delete the ChangePassword page and all password UI; align
  login/auth/api/types with the passwordless contract; add the
  migration and op-login approval flows.
- i18n: convert ImageBuildPage durations/status badges and
  ServerLuckPerms strings to translation keys; drop 72 orphan keys
  per locale; unify the title as "Felis - Console".

Plugins (all six rebuilt):
- Velocity waiting router returns 503 at_capacity during wake;
  MOTD/control-channel copy and config comments.
- Paper zh menu title; Limbo bind-code TTL 600s with panel_url
  preference; unified /link lines in fabric/forge/neoforge; shared
  link-client javadoc contract fixes.

Docs: openapi.yaml, sequence-diagrams.md, deploy/limbo/README.md and
plugins/README.md aligned with the implementation.

BREAKING CHANGE: migration 0017 irreversibly drops
users.password_hash and users.must_change_password; password login
cannot be restored after migrating.

internal/naming/naming.go

@@ -23,6 +23,7 @@ var reserved = map[string]struct{}{
 	"lobby":    {},
 	"admin":    {},
 	"panel":    {},
+	"console":  {}, // the player web console (console.<root>); op.console carries a dot and can never collide
 	"api":      {},
 	"felis":    {},
 	"velocity": {},
@@ -112,12 +113,6 @@ func ValidateSystemServerName(name string) error {
 	return nil
 }
 
-// IsReserved reports whether label is on the reserved list.
-func IsReserved(label string) bool {
-	_, ok := reserved[label]
-	return ok
-}
-
 // worldVolumeName mirrors operator.dataVolumeName: the per-server StatefulSet's
 // volumeClaimTemplate is named "world", so a single-replica server's world PVC
 // is "world-<name>-0". This is the one naming convention shared by the operator