Add interview agent settings UI and lifespan initialization

- Initialize default prompt settings at app startup via lifespan handler
- Add custom compact Settings UI for interview_agent category with:
  - Inline number input for max_followups_per_opener
  - Textarea for user_preference (tone + tacit knowledge focus)
  - Single "Save Changes" button per category
- Rename expert_guidance to user_preference across backend and frontend
- Add follow-up counter function for tracking questions since last opener

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Refactor semaphore multithreaded tests for improved validation

- Removed redundant assertions for loop IDs and enhanced the logic to ensure that the number of semaphore entries in the dictionary corresponds to unique loop IDs.
- Added checks to verify that each unique loop ID has a corresponding semaphore with the correct limit, improving test reliability and clarity.
- Updated comments to clarify the rationale behind the validation logic, addressing potential timing and memory reuse issues.

Merge pull request #449 from aitomatic/web-search-resource

add websearch resource

Blocking REPL execution with ESC cancellation implemented - UI blocks…

… until operations complete - Progress indicators for long operations - ESC key cancellation support - Better user experience for synchronous operations

Clear marker before implementing polling-based REPL execution with ES…

…C cancellation - py_reason converted to synchronous execution - Ready to implement smart blocking with polling and ESC cancellation

🎉 MILESTONE: Lambda expressions with conditional expressions complete

✅ COMPLETED FEATURES:
- Lambda expressions: lambda params :: expr
- Struct receivers: lambda (self: StructType) params :: expr
- Conditional expressions: lambda x :: x if x > 0 else -x
- Nested conditionals with right-associative parsing
- Full integration with Dana language infrastructure

🔧 TECHNICAL IMPLEMENTATION:
- Grammar: conditional_expr rule with proper precedence
- AST: ConditionalExpression node with condition/branches
- Transformer: Smart handling of optional grammar parts
- Executor: Truthiness-based condition evaluation

📊 TESTING STATUS:
- All functional tests passing
- Comprehensive conditional expression patterns working
- Previously commented-out lambda tests now functional
- Production-ready with error handling

🎯 USAGE EXAMPLES:
get_first = lambda lst :: lst[0] if len(lst) > 0 else None
max_func = lambda a, b :: a if a > b else b
classify = lambda x :: 'positive' if x > 0 else ('zero' if x == 0 else 'negative')

This milestone represents complete lambda expression functionality in Dana.

Phase 1 Complete: deliver keyword with await all strategy - REVERSION…

… MARKER

Release 0.1.0 – Initial milestone release

- Introduced core features and foundational functionality
- Completed initial implementation and basic testing
- Marking the first significant milestone for early feedback and iteration
- Ready for limited user evaluation and further enhancements