1. models.py — enriched Field descriptions with:
   - ✓/✗ query examples in descriptions
   - ILIKE semantics for city/district/metro
   - currency+price coupling warnings
   - rooms_count: 0=studio note
   - pagination strategy hints
   - Removed min_similarity from SearchSimilarInput (now hardcoded 0.7 in tools.py)

2. tools.py — added intelligent response layers:
   - _build_fallback_hint() — returns strategy tips on 0 results
     (switch tool, drop filters, simplify query, check language)
   - _build_invalid_query_hint() — detects stop-words & short queries,
     returns formatting tips with good/bad examples
   - describe_schema() enriched with:
     - usage_guidelines (when vector vs FTS)
     - query_examples (good/bad for both search types)
     - filter_combinations (recommended / avoid)
     - pagination_strategy

3. main.py — enriched tool docstrings with:
   - "When to use" vs other tools
   - Filter best practices
   - Fallback behavior description
   - Added @mcp.prompt() 'search_guide' — full agent guide
   - Added module docstring with server purpose, data scope, language

4. test_models.py — updated for removed min_similarity,
   added tests for description hints presence

10 tests pass, ruff clean.

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