Implement Gladiator character parsing and tests

[themuffinator]

Summary

• replace the ai_character loader stub with a parser that resolves Gladiator character scripts, stores traits, and exposes typed accessors
• publish the character profile interface through bot_character.h for downstream callers
• add a cmocka-based fixture that loads bots/babe_c.c and asserts chat, aggression, and grapple values

Testing

• cmake -S . -B build -DBUILD_TESTING=ON (fails: FetchContent clone of cmocka returns HTTP 403 in the execution environment)

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https://chatgpt.com/codex/tasks/task_e_6903c61972448328b3d4026ee8ec935a