fix: resolve CI test failures by removing unused imports and updating workflow paths

- Created models.py with HistoryEntry and SearchResult classes
- Created database.py with Database wrapper class
- Fixed test files to use actual implementation APIs
- Fixed conftest.py SearchResult fixture field names

src/shell_history_search/core/search.py

@@ -1,21 +1,12 @@
 import sqlite3
-from dataclasses import dataclass
 from pathlib import Path
 from typing import Optional
 
 from ..db import init_database, get_db_path
+from ..models import SearchResult
 from .embeddings import EmbeddingService
 
 
-@dataclass
-class SearchResult:
-    command: str
-    shell_type: str
-    timestamp: Optional[int]
-    similarity: float
-    command_id: int
-
-
 class SearchEngine:
     def __init__(
         self,