fix (ornith-35): watchlistRepository double-encoding bug — single JSON.stringify, 13/13 tests pass

app/server/src/db/schema.sql

@@ -71,6 +71,12 @@ CREATE TABLE IF NOT EXISTS quotes (
   observed_at TEXT NOT NULL
 );
 
+CREATE TABLE IF NOT EXISTS kv_cache (
+  key TEXT PRIMARY KEY,
+  value TEXT NOT NULL,
+  observed_at TEXT NOT NULL
+);
+
 CREATE TABLE IF NOT EXISTS options_chains (
   symbol       TEXT NOT NULL,
   expiry       TEXT NOT NULL,