fix: improve chunking logic in Chunker class and enhance smart search tool with comprehensive features

- Updated the Chunker class to adjust the window movement logic, ensuring proper handling of overlap lines.
- Introduced a new smart search tool with features including intent classification, CodexLens integration, multi-backend search routing, and index status checking.
- Implemented various search modes (auto, hybrid, exact, ripgrep, priority) with detailed metadata and error handling.
- Added support for progress tracking during index initialization and enhanced output transformation based on user-defined modes.
- Included comprehensive documentation for usage and parameters in the smart search tool.

codex-lens/src/codexlens/semantic/chunker.py

@@ -150,8 +150,13 @@ class Chunker:
                 chunk_idx += 1
 
             # Move window, accounting for overlap
-            start = end - overlap_lines
-            if start >= len(lines) - overlap_lines:
+            step = lines_per_chunk - overlap_lines
+            if step <= 0:
+                step = 1  # Failsafe to prevent infinite loop
+            start += step
+
+            # Break if we've reached the end
+            if end >= len(lines):
                 break
 
         return chunks