2.0.0: AI Code Chat + Explorer overhaul

2.0.0 — AI Code Chat + Explorer overhaul (36 commits)

AI Chat

• Copilot-style panel: local-LLM ReAct agent (search/neighbors/code/blast), lookup trace with clickable chips, Show on graph
• Ancestor walk-up, Explorer scope, fuzzy project match, cross-turn memory
• Provider management: Ollama + OpenAI-compatible presets, auto-fill, file-persisted keys
• Markdown answers, copy buttons, en-US/zh-TW prompts, draggable/resizable panel

Explorer & 3D

• Tree decoupled from LOD (always full), nested symbols, legend colors
• Walk-up locate, focus pill + full-chain lighting, file labels, WASD flight, dblclick refit, help dialog, settle re-aim

Packaging

• Bundled CLI resolver covers packaged app.asar.unpacked layout
• Version 2.0.0 everywhere, emoji-free README with new feature section