feat: Display AI reasoning/thinking blocks in chat interface (#152)

* feat: Add reasoning/thinking blocks display in chat interface

* feat: add multi-provider options support and replace custom reasoning UI with AI Elements

* resolve conflicting reasoning configs and correct provider-specific reasoning parameters

* try to solve conflict

* fix: simplify reasoning display and remove unnecessary dependencies

- Remove Streamdown dependency (~5MB) - reasoning is plain text only
- Fix Bedrock providerOptions merging for Claude reasoning configs
- Remove unsupported DeepSeek reasoning configuration
- Clean up unused environment variables (REASONING_BUDGET_TOKENS, REASONING_EFFORT, DEEPSEEK_REASONING_*)
- Remove dead commented code from route.ts

Reasoning blocks contain plain thinking text and don't need markdown/diagram/code rendering.

* feat: comprehensive reasoning support improvements

Major improvements:
- Auto-enable reasoning display for all supported models
- Fix provider-specific reasoning configurations
- Remove unnecessary Streamdown dependency (~5MB)
- Clean up debug logging

Provider changes:
- OpenAI: Auto-enable reasoningSummary for o1/o3/gpt-5 models
- Google: Auto-enable includeThoughts for Gemini 2.5/3 models
- Bedrock: Restrict reasoningConfig to only Claude/Nova (fixes MiniMax error)
- Ollama: Add thinking support for qwen3-like models

Other improvements:
- Remove ENABLE_REASONING toggle (always enabled)
- Fix Bedrock providerOptions merging for Claude
- Simplify reasoning component (plain text rendering)
- Clean up unused environment variables

* fix: critical bugs and documentation gaps in reasoning support

Critical fixes:
- Fix Bedrock shallow merge bug (deep merge preserves anthropicBeta + reasoningConfig)
- Add parseInt validation with parseIntSafe helper (prevents NaN errors)
- Validate all numeric env vars with min/max ranges

Documentation improvements:
- Add BEDROCK_REASONING_BUDGET_TOKENS and BEDROCK_REASONING_EFFORT to env.example
- Add OLLAMA_ENABLE_THINKING to env.example
- Update JSDoc with accurate env var list and ranges

Code cleanup:
- Remove debug console.log statements from route.ts
- Refactor duplicate providerOptions assignments

---------

Co-authored-by: Dayuan Jiang <34411969+DayuanJiang@users.noreply.github.com>
Co-authored-by: Dayuan Jiang <jdy.toh@gmail.com>

components/ui/collapsible.tsx

@@ -0,0 +1,33 @@
+"use client"
+
+import * as CollapsiblePrimitive from "@radix-ui/react-collapsible"
+
+function Collapsible({
+  ...props
+}: React.ComponentProps<typeof CollapsiblePrimitive.Root>) {
+  return <CollapsiblePrimitive.Root data-slot="collapsible" {...props} />
+}
+
+function CollapsibleTrigger({
+  ...props
+}: React.ComponentProps<typeof CollapsiblePrimitive.CollapsibleTrigger>) {
+  return (
+    <CollapsiblePrimitive.CollapsibleTrigger
+      data-slot="collapsible-trigger"
+      {...props}
+    />
+  )
+}
+
+function CollapsibleContent({
+  ...props
+}: React.ComponentProps<typeof CollapsiblePrimitive.CollapsibleContent>) {
+  return (
+    <CollapsiblePrimitive.CollapsibleContent
+      data-slot="collapsible-content"
+      {...props}
+    />
+  )
+}
+
+export { Collapsible, CollapsibleTrigger, CollapsibleContent }