Use gemma4 cloud model by default

Support Ollama Cloud API key

Agent improvements: mandatory planning, tool cleanup, smart_edit fixes ...

- Planning now mandatory on first message of every session (force_plan)
- RESOURCES, COMMITMENTS, ATOMICITY fields added to planning phase 1
- Todo auto-injected at iteration 0 so model tracks steps immediately
- Execution trigger injected after plan to prevent model treating plan as response
- Split developer profile: tool_developer (Navi tools) vs developer (general code)
- Simplified persona.txt: trimmed redundant content now handled by mechanics
- AIHelper.ask(): 120s timeout via asyncio.wait_for to prevent smart_edit hangs
- filesystem._smart_edit(): atomic write via temp file + os.replace()
- Removed 5 junk user tools (game project artifacts, trivial utilities)
- Removed instagram tools (to be rewritten); cleaned enabled.json

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>