Fixes#6259. Three bugs fixed:
1. Config key mismatch: _get_client() and _start_daemon() read
'llmApiKey' (camelCase) but save_config() stores 'llm_api_key'
(snake_case). The config value was never read — only the env var
fallback worked.
2. Missing base URL support: users on OpenRouter or custom endpoints
had no way to configure HINDSIGHT_API_LLM_BASE_URL through setup.
Added llm_base_url to config schema with empty default, passed
conditionally to HindsightEmbedded constructor.
3. Daemon config change detection: config_changed now also checks
HINDSIGHT_API_LLM_BASE_URL, and the daemon profile .env includes
the base URL when set.
Keeps HINDSIGHT_API_LLM_API_KEY (with double API) in the daemon
profile .env — this matches the upstream hindsight .env.example
convention.