feat(communication): add room visibility and project chat controls

backend/db/migrations/0078_chat_visibility.sql

@@ -0,0 +1,8 @@
+ALTER TABLE "projects" ADD COLUMN IF NOT EXISTS "chat_enabled" boolean NOT NULL DEFAULT true;
+--> statement-breakpoint
+CREATE TABLE "communication_hidden_rooms" (
+    "tenant_id" bigint NOT NULL REFERENCES "tenants"("id") ON DELETE CASCADE,
+    "user_id" uuid NOT NULL REFERENCES "auth_users"("id") ON DELETE CASCADE,
+    "room_key" text NOT NULL,
+    PRIMARY KEY ("tenant_id", "user_id", "room_key")
+);