feat(frequency_lookup): add get_freq_data() for batch frequency access

Exposes the full word→rank dict for use by the upcoming sentence_difficulty
module without requiring per-word lookups.

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

frequency_lookup.py

@@ -74,6 +74,16 @@ def get_frequency_rank(word_no_nikkud: str) -> int | None:
     return _freq.get(clean)
 
 
+def get_freq_data() -> dict[str, int]:
+    """Return the full frequency dict (word -> rank).
+
+    Auto-loads from cache if not yet loaded.
+    """
+    if not _freq:
+        load()
+    return _freq
+
+
 if __name__ == "__main__":
     logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")
     load()