refactor(server): move pending interactions and SSE fan-out to Postgres

db/migrations/20260518000000_pending_interactions.sql

@@ -0,0 +1,49 @@
+-- migrate:up
+
+-- Per-question state for the chat-interaction bridge — moved out of the
+-- gateway's in-process Map so a button click that lands on pod B can claim
+-- a question registered on pod A. The bridge keeps a small per-pod cache for
+-- the platform `SentMessage` (used to edit the original card on click) since
+-- that's a non-serializable SDK handle; everything that matters for routing
+-- the click back into the worker (PostedQuestion + connection context) lives
+-- here.
+--
+-- The claim path scopes by `(id, organization_id, connection_id,
+-- expected_user_id)` — keying by `id` alone would let a click from one
+-- connection or one user consume a question registered for another. The
+-- columns are NOT NULL so the SQL claim is a single index hit with no
+-- branching for NULL semantics.
+
+CREATE TABLE public.pending_interactions (
+  id text PRIMARY KEY,
+  organization_id text NOT NULL REFERENCES public.organization(id) ON DELETE CASCADE,
+  connection_id text NOT NULL,
+  expected_user_id text NOT NULL,
+  entry_payload jsonb NOT NULL,
+  created_at timestamp with time zone NOT NULL DEFAULT now(),
+  claimed_at timestamp with time zone
+);
+
+-- Claim path is
+--   UPDATE pending_interactions
+--      SET claimed_at = now()
+--    WHERE id = $1
+--      AND organization_id = $2
+--      AND connection_id = $3
+--      AND expected_user_id = $4
+--      AND claimed_at IS NULL
+--   RETURNING entry_payload
+-- — a partial index on the unclaimed predicate keeps the lookup index-only.
+CREATE INDEX idx_pending_interactions_unclaimed
+  ON public.pending_interactions (id, organization_id, connection_id, expected_user_id)
+  WHERE claimed_at IS NULL;
+
+-- Background sweeper drops rows older than 24h; index keeps that scan cheap.
+CREATE INDEX idx_pending_interactions_created_at
+  ON public.pending_interactions (created_at);
+
+-- migrate:down
+
+DROP INDEX IF EXISTS public.idx_pending_interactions_created_at;
+DROP INDEX IF EXISTS public.idx_pending_interactions_unclaimed;
+DROP TABLE IF EXISTS public.pending_interactions;

db/schema.sql

@@ -1419,6 +1419,20 @@ CREATE TABLE public.organization_lobu_links (
     updated_at timestamp with time zone DEFAULT now() NOT NULL
 );
 
+--
+-- Name: pending_interactions; Type: TABLE; Schema: public; Owner: -
+--
+
+CREATE TABLE public.pending_interactions (
+    id text NOT NULL,
+    organization_id text NOT NULL,
+    connection_id text NOT NULL,
+    expected_user_id text NOT NULL,
+    entry_payload jsonb NOT NULL,
+    created_at timestamp with time zone DEFAULT now() NOT NULL,
+    claimed_at timestamp with time zone
+);
+
 --
 -- Name: personal_access_tokens; Type: TABLE; Schema: public; Owner: -
 --
@@ -2633,6 +2647,13 @@ ALTER TABLE ONLY public.organization
 ALTER TABLE ONLY public.organization
     ADD CONSTRAINT organization_slug_key UNIQUE (slug);
 
+--
+-- Name: pending_interactions pending_interactions_pkey; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.pending_interactions
+    ADD CONSTRAINT pending_interactions_pkey PRIMARY KEY (id);
+
 --
 -- Name: personal_access_tokens personal_access_tokens_pkey; Type: CONSTRAINT; Schema: public; Owner: -
 --
@@ -3613,6 +3634,18 @@ CREATE INDEX idx_notification_targets_user_all ON public.notification_targets US
 
 CREATE INDEX idx_notification_targets_user_unread ON public.notification_targets USING btree (user_id, delivered_at DESC) WHERE (read_at IS NULL);
 
+--
+-- Name: idx_pending_interactions_created_at; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX idx_pending_interactions_created_at ON public.pending_interactions USING btree (created_at);
+
+--
+-- Name: idx_pending_interactions_unclaimed; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX idx_pending_interactions_unclaimed ON public.pending_interactions USING btree (id, organization_id, connection_id, expected_user_id) WHERE (claimed_at IS NULL);
+
 --
 -- Name: idx_personal_access_tokens_worker_id; Type: INDEX; Schema: public; Owner: -
 --
@@ -4768,6 +4801,13 @@ ALTER TABLE ONLY public.organization_lobu_links
 ALTER TABLE ONLY public.organization_lobu_links
     ADD CONSTRAINT organization_lobu_links_organization_id_fkey FOREIGN KEY (organization_id) REFERENCES public.organization(id) ON DELETE CASCADE;
 
+--
+-- Name: pending_interactions pending_interactions_organization_id_fkey; Type: FK CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.pending_interactions
+    ADD CONSTRAINT pending_interactions_organization_id_fkey FOREIGN KEY (organization_id) REFERENCES public.organization(id) ON DELETE CASCADE;
+
 --
 -- Name: personal_access_tokens personal_access_tokens_organization_id_fkey; Type: FK CONSTRAINT; Schema: public; Owner: -
 --
@@ -5030,4 +5070,5 @@ INSERT INTO public.schema_migrations (version) VALUES
     ('20260517050000'),
     ('20260517060000'),
     ('20260517150000'),
-    ('20260517160000');
+    ('20260517160000'),
+    ('20260518000000');