ST-1239: Atomische database-migratie — todos naar ideas + droppen todos-tabel (#132)

* feat(cleanup): verwijder Todo's navlink en todo-referenties uit marketing page [cmotto5ia000nx3178lq6xk8d]

- nav-bar.tsx: Todo's navLink verwijderd; Ideas-link blijft staan
- app/page.tsx: /todos quick-access link, feature-entry en /api/todos API-doc verwijderd

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat(cleanup): verwijder app/(app)/todos/ en components/todos/ [cmottjvzo000cx3172472cu4g]

* test(cleanup): verwijder POST /api/todos import en describe-block uit security.test.ts [cmotto5jn000px317kjqlba89]

- Import 'POST as postTodo' uit verwijderde todos-route verwijderd
- describe('POST /api/todos') sectie (3 tests) verwijderd
- 73 testfiles / 561 tests groen

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test(cleanup): verwijder __tests__/api/todos.test.ts en __tests__/actions/todos-promote-idea.test.ts [cmottjw1u000fx317igq27mh5]

* feat(cleanup): verwijder actions/todos.ts en app/api/todos/route.ts; verplaats updateRolesAction naar actions/settings.ts [cmottjvy9000ax3173sgfjcqs]

* feat(db): migratie todos→ideas, counters bijwerken, todos dropt [cmotto5fh000jx317r7c5srvb]

Nieuwe Prisma-migratie die in één transactie actieve todos omzet naar
DRAFT-ideas met unieke IDEA-NNN codes, idea_code_counter per user
bijwerkt, en de todos-tabel dropt.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat(schema): verwijder Todo model en relaties uit prisma/schema.prisma [cmottjvwu0008x317fwwodg3i]

* feat(cleanup): vervang open_todos door open_ideas in /api/products/:id/claude-context

Laatste prisma.todo-referentie verwijderd. Endpoint geeft nu open_ideas terug
(ideeën van de gebruiker voor dit product die niet gearchiveerd zijn en nog
niet status PLANNED hebben). Docs bijgewerkt in docs/api.md en
docs/api/rest-contract.md.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

prisma/migrations/20260507000000_migrate_todos_to_ideas/migration.sql

@@ -0,0 +1,59 @@
+BEGIN;
+
+WITH active_todos AS (
+  SELECT t.id, t.user_id, t.product_id, t.title, t.description, t.created_at
+  FROM todos t
+  WHERE t.done = false
+    AND t.archived = false
+    AND NOT EXISTS (
+      SELECT 1 FROM ideas i
+      WHERE i.user_id = t.user_id
+        AND lower(trim(i.title)) = lower(trim(t.title))
+    )
+),
+user_base AS (
+  SELECT ut.user_id, u.idea_code_counter AS base_counter
+  FROM (SELECT DISTINCT user_id FROM active_todos) ut
+  JOIN users u ON u.id = ut.user_id
+),
+ranked AS (
+  SELECT
+    at.user_id, at.product_id, at.title, at.description, at.created_at,
+    ub.base_counter,
+    ROW_NUMBER() OVER (PARTITION BY at.user_id ORDER BY at.created_at, at.id) AS rn
+  FROM active_todos at
+  JOIN user_base ub ON ub.user_id = at.user_id
+),
+inserted AS (
+  INSERT INTO ideas (
+    id, user_id, product_id, code, title, description,
+    status, archived, created_at, updated_at
+  )
+  SELECT
+    gen_random_uuid()::text,
+    user_id,
+    product_id,
+    'IDEA-' || lpad((base_counter + rn)::text, 3, '0'),
+    title,
+    description,
+    'DRAFT',
+    false,
+    created_at,
+    now()
+  FROM ranked
+  RETURNING user_id,
+    (regexp_replace(code, '^IDEA-0*', ''))::int AS used_counter
+)
+UPDATE users u
+SET idea_code_counter = sub.max_counter
+FROM (
+  SELECT user_id, MAX(used_counter) AS max_counter
+  FROM inserted
+  GROUP BY user_id
+) sub
+WHERE u.id = sub.user_id
+  AND sub.max_counter > u.idea_code_counter;
+
+DROP TABLE todos;
+
+COMMIT;