Add chunk_index validation and clean up SQL statement

Co-authored-by: Mte90 <403283+Mte90@users.noreply.github.com>

Author: Copilot

ai/analyzer.py

@@ -327,6 +327,12 @@ def _get_chunk_text(database_path: str, file_id: int, chunk_index: int) -> Optio
         # Extract the chunk
         if CHUNK_SIZE <= 0:
             return content
+        
+        # Validate chunk_index
+        if chunk_index < 0:
+            logger.warning(f"Invalid chunk_index {chunk_index} for file_id={file_id}")
+            return None
+        
         step = max(1, CHUNK_SIZE - CHUNK_OVERLAP)
         start = chunk_index * step
         end = min(start + CHUNK_SIZE, len(content))

db/operations.py

@@ -234,14 +234,14 @@ def store_file(database_path, path, content, language, last_modified=None, file_
     sqlite 'database is locked' errors in multithreaded scenarios.
     Supports incremental indexing with last_modified and file_hash tracking.
     Note: Does not store full file content in database (only snippet), content is read from filesystem when needed.
+    The content parameter is still required to generate the snippet.
     Returns lastrowid (same as the previous store_file implementation).
     """
     snippet = (content[:512] if content else "")
     sql = """
-        INSERT INTO files (path, content, language, snippet, last_modified, file_hash, updated_at) 
-        VALUES (?, NULL, ?, ?, ?, ?, datetime('now'))
+        INSERT INTO files (path, language, snippet, last_modified, file_hash, updated_at) 
+        VALUES (?, ?, ?, ?, ?, datetime('now'))
         ON CONFLICT(path) DO UPDATE SET 
-            content=NULL,
             language=excluded.language,
             snippet=excluded.snippet,
             last_modified=excluded.last_modified,