Intent switch detection false switch fix

[nuwangeek]

This pull request introduces a configurable minimum cosine similarity threshold for API tool classification, allowing more flexible and context-sensitive matching. It also updates the API tool endpoint test data and removes an obsolete import YAML file. The most important changes are grouped below:

Semantic Search & Classification Logic

• Added a min_cosine_override parameter to the semantic search (APISemanticSearcher.search) and classification (_try_api_tool_classification) methods, allowing callers to specify a custom minimum cosine threshold for matching. This enables more precise or relaxed matching depending on the context. The effective threshold is now always used for confidence evaluation and match filtering. [1] [2] [3] [4] [5] [6] [7]
• Introduced the constant API_TOOL_INTENT_SWITCH_THRESHOLD (set to 0.50) to require a higher cosine similarity when abandoning an active session and switching user intent. The classifier now uses this stricter threshold during intent switching. [1] [2] [3]

Test Data Updates

• Updated the get_vehicle_tax_info endpoint in test-endpoints.json with a new URL, method (GET), and expanded parameter list to reflect the latest API contract.
• Added a new endpoint, check_legal_eligibility, to the test endpoints for broader test coverage.

Cleanup

• Removed the obsolete DSL/Ruuter.private/rag-search/POST/ckb/agency_data_import.yml file, which is no longer needed.