feat(db): add oauth_clients table for dynamic client registration

* Introduced oauth_clients table with fields for client_id, client_name, redirect_uris, and created_at.
* Updated agent_persona_parts, agent_persona_skills, agent_persona_guardrails, agent_persona_traits, and arc_stage_parts tables to use unique constraints instead of primary keys for composite indexes.

schema/agent_personas.dbml

@@ -27,33 +27,35 @@ Table agent_parts {
 }
 
 Table agent_persona_parts {
+  id bigserial [pk]
   persona_id bigint [not null, ref: > agent_personas.id]
   part_id bigint [not null, ref: > agent_parts.id]
   part_order int [not null, default: 0]
   priority int [not null, default: 0]
 
   indexes {
-    (persona_id, part_id) [pk]
+    (persona_id, part_id) [uk]
     persona_id
   }
 }
 
 Table agent_persona_skills {
+  id bigserial [pk]
   persona_id bigint [not null, ref: > agent_personas.id]
   skill_id bigint [not null, ref: > agent_skills.id]
 
   indexes {
-    (persona_id, skill_id) [pk]
+    (persona_id, skill_id) [uk]
     persona_id
   }
 }
 
 Table agent_persona_guardrails {
+  id bigserial [pk]
   persona_id bigint [not null, ref: > agent_personas.id]
   guardrail_id bigint [not null, ref: > agent_guardrails.id]
 
   indexes {
-    (persona_id, guardrail_id) [pk]
     persona_id
   }
 }
@@ -71,11 +73,11 @@ Table agent_traits {
 }
 
 Table agent_persona_traits {
+  id bigserial [pk]
   persona_id bigint [not null, ref: > agent_personas.id]
   trait_id bigint [not null, ref: > agent_traits.id]
 
   indexes {
-    (persona_id, trait_id) [pk]
     persona_id
   }
 }
@@ -100,15 +102,17 @@ Table arc_stages {
 }
 
 Table arc_stage_parts {
+  id bigserial [pk]
   stage_id bigint [not null, ref: > arc_stages.id]
   part_id bigint [not null, ref: > agent_parts.id]
 
   indexes {
-    (stage_id, part_id) [pk]
+    (stage_id, part_id)
   }
 }
 
 Table persona_arc {
+  id bigserial [pk]
   persona_id bigint [pk, ref: > agent_personas.id]
   arc_id bigint [not null, ref: > character_arcs.id]
   current_stage_id bigint [not null, ref: > arc_stages.id]

schema/oauth_clients.dbml

@@ -0,0 +1,8 @@
+// OAuth 2.0 Dynamic Client Registration (RFC 7591)
+Table oauth_clients {
+  id            bigserial    [pk]
+  client_id     text         [unique, not null]
+  client_name   text         [not null, default: '']
+  redirect_uris "text[]"     [not null, default: `'{}'`]
+  created_at    timestamptz  [not null, default: `now()`]
+}