feat: Story 8 - Collapsible tool outputs + autonomous coding improvements

Implemented Story 8: Collapsible Tool Outputs
- Tool outputs now render in <details>/<summary> elements, collapsed by default
- Summary shows tool name with key argument (e.g., ▶ read_file(src/main.rs))
- Added arrow rotation animation and scrollable content (max 300px)
- Enhanced tool_calls display to show arguments inline
- Added CSS styling for dark theme consistency

Fixed: LLM autonomous coding behavior
- Strengthened system prompt with explicit examples and directives
- Implemented triple-reinforcement system (primary prompt + reminder + message prefixes)
- Improved tool descriptions to be more explicit and action-oriented
- Increased MAX_TURNS from 10 to 30 for complex agentic workflows
- Added debug logging for Ollama requests/responses
- Result: GPT-OSS (gpt-oss:20b) now successfully uses write_file autonomously

Documentation improvements
- Created MODEL_SELECTION.md guide with recommendations
- Updated PERSONA.md spec to emphasize autonomous agent behavior
- Updated UI_UX.md spec with collapsible tool output requirements
- Updated SDSW workflow: LLM archives stories and performs squash merge

Cleanup
- Removed unused ToolTester.tsx component

.living_spec/stories/09_remove_scroll_bars.md

@@ -0,0 +1,3 @@
+there is a scroll bar on the right that looks gross. also a horizontal scroll bar that should come out
+
+story needs to be worked through