Module file_index 

File index for efficient log navigation (Option 3 Implementation)

This module provides a lightweight index structure that scans the file once to identify log boundaries and metadata without full parsing.

How it works:

1. Fast Initial Scan: On file open, scan all lines to find log boundaries
2. Extract Metadata: For each log, extract timestamp and layer (cheap operation)
3. Build Index: Store line ranges and metadata for each log
4. Lazy Parsing: Parse full log content only when needed (on navigation)
5. Smart Caching: Cache parsed logs to avoid re-parsing

Benefits:

• Fast file loading (~0.5s for 10k logs)
• Know total log count immediately
• Efficient layer filtering (no need to parse disabled layers)
• Instant navigation (index knows where each log is)

Structs

FileIndex

Index structure for efficient file navigation

LogMetadata

Metadata for a single log entry