Add v2_ux.md specification with detailed UX patterns

Based on MCPJam Inspector analysis:
- Server connection card with status indicators
- Resizable panel layouts for Tools/Resources/Prompts screens
- Form generation from JSON Schema
- Error handling patterns (inline errors, retry count, doc links)

Also updates nav links in all spec files to include v2_ux.md.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

specification/v2_tech_stack.md

@@ -1,6 +1,6 @@
 # Inspector V2 Tech Stack
 
-### [Brief](README.md) | [V1 Problems](v1_problems.md) | [V2 Scope](v2_scope.md) | V2 Tech Stack
+### [Brief](README.md) | [V1 Problems](v1_problems.md) | [V2 Scope](v2_scope.md) | V2 Tech Stack | [V2 UX](v2_ux.md)
 
 ## Table of Contents
   * [Web Client](#web-client)