Add MCP server so Claude (or any MCP client) can reprogram VersaPad directly

Wraps the existing protocol/serial/combined-config layers as MCP tools
(set_button_key, set_encoder_consumer, set_macro, load_from_board,
write_to_board, ...) instead of requiring hand-written JSON + manual
GUI import. Registered at user scope via `claude mcp add`.

versapad_data.py

@@ -99,6 +99,35 @@ def consumer_choices():
     return sorted(_CONSUMER_NAMES.items())
 
 
+_KEY_CODE_BY_NAME = {name: code for code, name in _SPECIAL_KEYS.items()}
+_CONSUMER_ID_BY_NAME = {name: cid for cid, name in _CONSUMER_NAMES.items()}
+
+
+def hid_key_code_for_name(name):
+    """z.B. 'S' -> 0x16. Wirft ValueError mit Vorschlaegen bei unbekanntem Namen."""
+    if name not in _KEY_CODE_BY_NAME:
+        raise ValueError(f"Unbekannte Taste {name!r}. Gueltige Namen: {sorted(_KEY_CODE_BY_NAME)}")
+    return _KEY_CODE_BY_NAME[name]
+
+
+def consumer_id_for_name(name):
+    """z.B. 'Play / Pause' -> 0xCD. Wirft ValueError mit Vorschlaegen bei unbekanntem Namen."""
+    if name not in _CONSUMER_ID_BY_NAME:
+        raise ValueError(f"Unbekannte Medienaktion {name!r}. Gueltige Namen: {sorted(_CONSUMER_ID_BY_NAME)}")
+    return _CONSUMER_ID_BY_NAME[name]
+
+
+def modifier_bits_for_names(names):
+    """['Strg','Shift'] -> 0x03. Wirft ValueError bei unbekanntem Namen."""
+    valid = {name: bit for bit, name in MODIFIER_BITS}
+    bits = 0
+    for name in names:
+        if name not in valid:
+            raise ValueError(f"Unbekannter Modifier {name!r}. Gueltig: {sorted(valid)}")
+        bits |= valid[name]
+    return bits
+
+
 def macro_step_label(step):
     """step: {'keycode','modifier'} -> z.B. 'Strg+S'. Reine Keycode/Modifier-Variante
     von hid_key_label() (dort steckt beides in einem 16-Bit data-Feld, hier getrennt)."""