feat: global block library tree + grouping tool — 19 files, 588 tests green

backend/src/database/schema.sql

@@ -133,3 +133,27 @@ CREATE INDEX IF NOT EXISTS idx_blocks_drawing ON blocks(drawing_id);
  
  CREATE INDEX IF NOT EXISTS idx_notifications_user ON notifications(user_id);
  CREATE INDEX IF NOT EXISTS idx_shares_project ON project_shares(project_id);
+
+-- ─── Global Block Folders ─────────────────────────────
+CREATE TABLE IF NOT EXISTS global_block_folders (
+  id TEXT PRIMARY KEY,
+  name TEXT NOT NULL,
+  parent_id TEXT,
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  FOREIGN KEY (parent_id) REFERENCES global_block_folders(id) ON DELETE CASCADE
+);
+
+-- ─── Global Blocks ──────────────────────────────────────
+CREATE TABLE IF NOT EXISTS global_blocks (
+  id TEXT PRIMARY KEY,
+  folder_id TEXT,
+  name TEXT NOT NULL,
+  block_data TEXT NOT NULL DEFAULT '{}',
+  svg_data TEXT,
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT (datetime('now')),
+  FOREIGN KEY (folder_id) REFERENCES global_block_folders(id) ON DELETE SET NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_global_blocks_folder ON global_blocks(folder_id);
+CREATE INDEX IF NOT EXISTS idx_global_block_folders_parent ON global_block_folders(parent_id);