Add WebSocket support (#12)

backend/sync_server/src/database/migrations/20241207143519_bootstrap.sql

@@ -1,21 +0,0 @@
-CREATE TABLE IF NOT EXISTS documents (
-    vault_update_id INTEGER NOT NULL PRIMARY KEY,
-    document_id TEXT NOT NULL,
-    relative_path TEXT NOT NULL,
-    updated_date TIMESTAMP NOT NULL,
-    content BLOB NOT NULL,
-    is_deleted BOOLEAN NOT NULL
-);
-
-CREATE VIEW IF NOT EXISTS latest_document_versions AS
-SELECT d.*
-FROM documents d
-INNER JOIN (
-    SELECT MAX(vault_update_id) AS max_version_id
-    FROM documents
-    GROUP BY document_id
-) max_versions
-ON d.vault_update_id = max_versions.max_version_id;
-
-CREATE INDEX IF NOT EXISTS idx_documents_vault_id_relative_path
-ON documents (relative_path);