feat(admin-web): add Feishu Application Connection admin page

ADR-0021 pins the organization<->Feishu application binding to 1:1 and
the backend already exposes
  GET    /api/org/:orgSlug/feishu-application-connection
  PUT    /api/org/:orgSlug/feishu-application-connection  (rotate/create)
  DELETE /api/org/:orgSlug/feishu-application-connection  (disable)
backed by FeishuApplicationConnectionService with versioned envelopes
(ADR-0024). The org-admin SPA had no surface for it, so the only
connection type the spec requires was unmanageable from the admin UI.

Add a Feishu page that reads the current connection (status, redacted
app fingerprint, active version, updatedAt), rotates credentials with
appId/appSecret/botOpenId (+ optional verificationToken/encryptKey) as
the backend requires, and disables with confirmation. Add the matching
api client (feishuApplication / rotateFeishuApplication /
disableFeishuApplication), a feishu nav icon and a nav entry.

hub/admin-web/src/routes/+layout.svelte

@@ -23,7 +23,8 @@
 		{ key: 'members', label: '成员', icon: 'members' as const },
 		{ key: 'teams', label: '团队', icon: 'teams' as const },
 		{ key: 'projects', label: '项目', icon: 'projects' as const },
-		{ key: 'provider', label: '供应方', icon: 'provider' as const }
+		{ key: 'provider', label: '供应方', icon: 'provider' as const },
+		{ key: 'feishu', label: '飞书', icon: 'feishu' as const }
 	];
 
 	function isAdmin(org: OrgMembership): boolean {