feat(llm): add LLM integration instructions and handler

* Serve LLM instructions at `/llm`
* Include markdown content for memory instructions
* Update README with LLM integration details
* Add tests for LLM instructions handler
* Modify database migrations to use GUIDs for thoughts and projects

migrations/002_create_thoughts.sql

@@ -1,10 +1,12 @@
 create table if not exists thoughts (
-  id uuid default gen_random_uuid() primary key,
-  content text not null,
-  embedding vector(1536),
-  metadata jsonb default '{}'::jsonb,
+  id         bigserial   primary key,
+  guid       uuid        not null default gen_random_uuid(),
+  content    text        not null,
+  embedding  vector(1536),
+  metadata   jsonb       default '{}'::jsonb,
   created_at timestamptz default now(),
-  updated_at timestamptz default now()
+  updated_at timestamptz default now(),
+  constraint thoughts_guid_unique unique (guid)
 );
 
 create index if not exists thoughts_embedding_hnsw_idx

migrations/003_add_projects.sql

@@ -1,12 +1,14 @@
 create table if not exists projects (
-  id uuid default gen_random_uuid() primary key,
-  name text not null unique,
-  description text,
-  created_at timestamptz default now(),
-  last_active_at timestamptz default now()
+  id             bigserial   primary key,
+  guid           uuid        not null default gen_random_uuid(),
+  name           text        not null unique,
+  description    text,
+  created_at     timestamptz default now(),
+  last_active_at timestamptz default now(),
+  constraint projects_guid_unique unique (guid)
 );
 
-alter table thoughts add column if not exists project_id uuid references projects(id);
+alter table thoughts add column if not exists project_id uuid references projects(guid);
 alter table thoughts add column if not exists archived_at timestamptz;
 
 create index if not exists thoughts_project_id_idx on thoughts (project_id);

migrations/004_create_thought_links.sql

@@ -1,7 +1,7 @@
 create table if not exists thought_links (
-  from_id uuid references thoughts(id) on delete cascade,
-  to_id uuid references thoughts(id) on delete cascade,
-  relation text not null,
+  from_id    bigint      not null references thoughts(id) on delete cascade,
+  to_id      bigint      not null references thoughts(id) on delete cascade,
+  relation   text        not null,
   created_at timestamptz default now(),
   primary key (from_id, to_id, relation)
 );

migrations/005_create_match_thoughts.sql

@@ -16,7 +16,7 @@ as $$
 begin
   return query
   select
-    t.id,
+    t.guid,
     t.content,
     t.metadata,
     1 - (t.embedding <=> query_embedding) as similarity,

migrations/007_embeddings_table.sql

@@ -1,7 +1,7 @@
 create table if not exists embeddings (
   id        bigserial   primary key,
   guid      uuid        not null default gen_random_uuid(),
-  thought_id uuid       not null references thoughts(id) on delete cascade,
+  thought_id uuid       not null references thoughts(guid) on delete cascade,
   model     text        not null,
   dim       int         not null,
   embedding vector      not null,

migrations/008_update_match_thoughts.sql

@@ -17,13 +17,13 @@ as $$
 begin
   return query
   select
-    t.id,
+    t.guid,
     t.content,
     t.metadata,
     1 - (e.embedding <=> query_embedding) as similarity,
     t.created_at
   from thoughts t
-  join embeddings e on e.thought_id = t.id
+  join embeddings e on e.thought_id = t.guid
   where 1 - (e.embedding <=> query_embedding) > match_threshold
     and t.archived_at is null
     and (embedding_model = '' or e.model = embedding_model)