feat(ui): add maintenance page for task management

* Implement maintenance page with task and log display
* Add backfill and metadata retry functionality
* Integrate grid component for project display in thoughts page
* Update types for maintenance tasks and logs
* Enhance sidebar and shell for new maintenance navigation

migrations/_old/003_add_projects.sql

@@ -0,0 +1,15 @@
+create table if not exists projects (
+  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(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);
+create index if not exists thoughts_archived_at_idx on thoughts (archived_at);