feat(reader): implement FEAT-01 Focus Zen Mode (100% vh/vw, auto-hiding HUD, hotkeys F/Esc, native fullscreen)

app/database.py

@@ -331,6 +331,8 @@ def _migrate(conn: sqlite3.Connection):
         title TEXT NOT NULL,
         subtitle TEXT DEFAULT '',
         golden_formula TEXT NOT NULL,
+        cheatsheet_table TEXT DEFAULT '',
+        detailed_notes TEXT DEFAULT '',
         contrast_explanation_json TEXT NOT NULL,
         journaling_prompt TEXT NOT NULL,
         exercises_json TEXT NOT NULL,
@@ -340,6 +342,18 @@ def _migrate(conn: sqlite3.Connection):
     conn.execute("CREATE INDEX IF NOT EXISTS idx_grammar_units_num ON grammar_units(unit_num);")
     conn.execute("CREATE INDEX IF NOT EXISTS idx_grammar_units_level ON grammar_units(level);")
 
+    # Safe migration: add cheatsheet_table and detailed_notes columns if not present
+    existing_grammar_cols = {
+        row[1] for row in conn.execute("PRAGMA table_info(grammar_units)").fetchall()
+    }
+    grammar_migrations = [
+        ("cheatsheet_table", "TEXT DEFAULT ''"),
+        ("detailed_notes", "TEXT DEFAULT ''"),
+    ]
+    for col, definition in grammar_migrations:
+        if col not in existing_grammar_cols:
+            conn.execute(f"ALTER TABLE grammar_units ADD COLUMN {col} {definition}")
+
     conn.execute("""
     CREATE TABLE IF NOT EXISTS grammar_progress (
         id INTEGER PRIMARY KEY AUTOINCREMENT,