v0.20.0: thinking blocks, chat windows overhaul, scroll fix

Backend:
- Add isThinking flag to agentEvent for text before tool calls
- Separate thinking from response text in runChatTurn and continue.go
- Persist thinking in a dedicated field in message content

Frontend:
- Add thinking field to MessageContent, ChatMessage, ChatTextEvent types
- Create ThinkingBlock.svelte — collapsible block with brain icon
- SSE handler moves text_delta content to thinking on isThinking flag
- Render thinking block between tools and response in ChatThread
- Fix chat window scroll reset on focus change (stable windowKeys order)
- Remove redundant #key id wrapper in WindowLayer
- Enlarge sidebar rail (24→32 default, 40→60 max)
- Remove glyph from sidebar, square graph at top
- Replace AgentTrace/ToolCallCard/UnifiedTimeline with TurnTrace/ToolLine

web/package.json

@@ -42,6 +42,7 @@
     "vitest": "^2.0.0"
   },
   "dependencies": {
+    "@joan/procedural-glyph-engine": "file:../../../../../private/tmp/orby-pkg",
     "@surdeddd/wmkit": "^0.3.0",
     "clsx": "^2.1.1",
     "d3-force": "^3.0.0",