fix(auth): make the owner role real — provisioning, staff doors, panel guards

Found live while verifying the admin email-edit fix: the Owner account could
not load /api/v1/users at all. Root cause: migration 0011 adds the 'owner'
role and gates every user-administration route on it, but NOTHING ever wrote
it. break-glass (UpsertOwner), the setup MC-bind (CompleteOwnerSetup), and the
re-provision path all forced 'admin', so in a fresh install the entire
owner tier — list/create/edit/disable/delete users, quotas, sessions — was
unreachable. The role was a dead letter in the other direction too: staff
predicates that predate the role did not know it.

- UpsertOwner and CompleteOwnerSetup now write role='owner'; the username-
  conflict arm re-asserts it, which is also the documented pre-0011 promotion
  path ("re-provision via break-glass"). InsertOperator stays plain 'admin'.
- Staff doors learn the role: op-login start/finish admit the Owner; the
  player email door refuses it like any staff account; the in-game approver
  check already used staffRole.
- Reclaim protection: IsProtectedAdminLink (and the break-glass bootstrap
  switch AdminExists) count admin OR owner — the Owner must never be displaced
  by a Mojang-priority reclaim.
- Panel guards make migration 0011's claim true now that owner rows exist: an
  owner can never be demoted, deleted, or disabled through the API (only the
  local break-glass console resets the identity); username/email edits still
  work.

Tests: pgint pins both provisioning paths, the protected-link predicate and
the reset/promote semantics; hermetic suites cover the owner-admitting staff
door, the owner-refusing player door, the three panel guards, and break-glass
attribution.

internal/api/auth.go

@@ -17,13 +17,13 @@ type Principal struct {
 	UserID string
 	// Email is the audited actor identity (spec §14: audit actor = Access email).
 	Email string
-	// Role is "admin" or "user" (mirrors users.role).
+	// Role is "owner", "admin", or "user" (mirrors users.role).
 	Role string
 	// ViaAdminAccess is true only when the request arrived through an admin-graded
 	// path: the admin.* Zero-Trust hostname (Cloudflare Access, the remote face) OR
 	// a local session presented on the op.console host (SessionAuth, the
 	// passwordless face). Admin-tier operations require it in addition to
-	// Role=="admin" (spec §14: ZT is graded by operation). A role=admin session
+	// a staff role (spec §14: ZT is graded by operation). A staff session
 	// arriving on the player console (console.*) never sets it.
 	ViaAdminAccess bool
 	// EmailVerified mirrors users.email_verified. The lockdown middleware gates
@@ -49,7 +49,7 @@ func staffRole(role string) bool {
 }
 
 // IsAdmin reports whether the principal may perform admin-tier operations.
-// Both the role claim and the admin Access path are required: a role=admin
+// Both the role claim and the admin Access path are required: a staff
 // session arriving on panel.* must not bypass the Zero-Trust boundary.
 // An owner implicitly passes this check (the owner role is a superset of admin).
 func (p *Principal) IsAdmin() bool {