feat(ui): add identity management for tenants and users

* Implement tenant and user creation in IdentityPage
* Add API calls for managing tenants and users
* Introduce tenant-scoped API requests
* Update sidebar to include identity navigation
* Create BooleanStatusBadge component for key status

schema/meta.dbml

@@ -6,7 +6,7 @@ Table chat_histories {
   channel text
   agent_id text
   project_id bigint [ref: > projects.id]
-  tenant_key text
+  tenant_id text [ref: > tenants.id]
   messages jsonb [not null, default: `'[]'`]
   summary text
   metadata jsonb [not null, default: `'{}'`]
@@ -16,7 +16,7 @@ Table chat_histories {
   indexes {
     session_id
     project_id
-    tenant_key
+    tenant_id
     channel
     agent_id
     created_at
@@ -48,7 +48,7 @@ Table learnings {
   source_type text
   source_ref text
   project_id bigint [ref: > projects.id]
-  tenant_key text
+  tenant_id text [ref: > tenants.id]
   related_thought_id bigint [ref: > thoughts.id]
   related_skill_id bigint [ref: > agent_skills.id]
   reviewed_by text
@@ -61,7 +61,7 @@ Table learnings {
 
   indexes {
     project_id
-    tenant_key
+    tenant_id
     category
     area
     status