feat: add chat sharing foundation (#25041)

coderd/database/dump.sql

@@ -242,7 +242,8 @@ CREATE TYPE api_key_scope AS ENUM (
     'ai_provider:create',
     'ai_provider:delete',
     'ai_provider:read',
-    'ai_provider:update'
+    'ai_provider:update',
+    'chat:share'
 );
 
 CREATE TYPE app_sharing_level AS ENUM (
@@ -1558,6 +1559,11 @@ CREATE TABLE chats (
     plan_mode chat_plan_mode,
     client_type chat_client_type DEFAULT 'api'::chat_client_type NOT NULL,
     last_turn_summary text,
+    user_acl jsonb DEFAULT '{}'::jsonb NOT NULL,
+    group_acl jsonb DEFAULT '{}'::jsonb NOT NULL,
+    CONSTRAINT chat_acl_only_on_root_chats CHECK ((((parent_chat_id IS NULL) AND (root_chat_id IS NULL)) OR ((user_acl = '{}'::jsonb) AND (group_acl = '{}'::jsonb)))),
+    CONSTRAINT chat_group_acl_not_null_jsonb CHECK (((group_acl IS NOT NULL) AND (jsonb_typeof(group_acl) = 'object'::text))),
+    CONSTRAINT chat_user_acl_not_null_jsonb CHECK (((user_acl IS NOT NULL) AND (jsonb_typeof(user_acl) = 'object'::text))),
     CONSTRAINT chats_pin_order_archived_check CHECK (((pin_order = 0) OR (archived = false))),
     CONSTRAINT chats_pin_order_parent_check CHECK (((pin_order = 0) OR (parent_chat_id IS NULL)))
 );
@@ -1642,9 +1648,12 @@ CREATE VIEW chats_expanded AS
     c.plan_mode,
     c.client_type,
     c.last_turn_summary,
+    COALESCE(root.user_acl, c.user_acl) AS user_acl,
+    COALESCE(root.group_acl, c.group_acl) AS group_acl,
     owner.username AS owner_username,
     owner.name AS owner_name
-   FROM (chats c
+   FROM ((chats c
+     LEFT JOIN chats root ON ((root.id = COALESCE(c.root_chat_id, c.parent_chat_id))))
      JOIN visible_users owner ON ((owner.id = c.owner_id)));
 
 CREATE TABLE connection_logs (