Add a max_data_length field option to api_options.proto for string/bytes
fields. When max_data_length < 128 and force = true, the code generator
uses encode_short_string_force() — a single call that writes the tag
byte, 1-byte length varint, and raw string data with no branching. Size
calculation simplifies from calc_length(1, size) to 2 + size.
Annotate entity fields across all 25 ListEntities*Response messages:
- name and object_id: max_data_length = 120, force = true (50 fields)
- icon: max_data_length = 63 (25 fields)
The 120 and 63 values match NAME_MAX_LENGTH and ICON_MAX_LENGTH in
esphome/core/config.py, validated at config time.
J. Nick Koston
87622c9a74