feat(tools): link thoughts and learnings

migrations/030_thought_learning_links.sql

@@ -0,0 +1,26 @@
+-- Many-to-many join table between thoughts and learnings.
+-- Allows a learning to reference multiple source thoughts and a thought to
+-- expose multiple related learnings, queryable in both directions.
+
+CREATE SEQUENCE IF NOT EXISTS public.identity_thought_learning_links_id
+  INCREMENT 1
+  MINVALUE 1
+  MAXVALUE 9223372036854775807
+  START 1
+  CACHE 1;
+
+CREATE TABLE IF NOT EXISTS public.thought_learning_links (
+  id bigint NOT NULL DEFAULT nextval('public.identity_thought_learning_links_id'),
+  thought_id bigint NOT NULL REFERENCES public.thoughts(id) ON DELETE CASCADE,
+  learning_id bigint NOT NULL REFERENCES public.learnings(id) ON DELETE CASCADE,
+  relation text NOT NULL DEFAULT 'source',
+  created_at timestamptz NOT NULL DEFAULT now(),
+  CONSTRAINT thought_learning_links_pkey PRIMARY KEY (id),
+  CONSTRAINT thought_learning_links_unique UNIQUE (thought_id, learning_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_thought_learning_links_thought_id
+  ON public.thought_learning_links (thought_id);
+
+CREATE INDEX IF NOT EXISTS idx_thought_learning_links_learning_id
+  ON public.thought_learning_links (learning_id);