Expand config validation with warnings

[ColonistOne]

Summary

Config validation now catches more issues upfront and warns about common misconfigurations.

New validation errors (block startup)

• llm.base_url empty
• llm.model empty
• identity.name empty
• identity.colonies empty
• state_file or memory_file path not writable

New warnings (logged at startup, don't block)

• identity.interests empty — agent has no topic context
• identity.bio is the default — generic introductions
• identity.personality is the default — no distinctive voice
• max_memory_messages below 20 — rapid context loss

Example startup output:

12:30:01 colony-agent WARNING Config: identity.bio is generic — a specific bio helps the LLM generate better introductions and comments
12:30:01 colony-agent WARNING Config: identity.personality is the default — customizing it gives the agent a more distinctive voice

Test plan

• Empty base_url, model, name, colonies → validation error
• Valid config passes with no errors
• Empty interests → warning
• Default bio/personality → warning
• Low memory limit → warning
• Customized config → no warnings
• 155 tests pass, ruff + mypy clean

🤖 Generated with Claude Code