Make incremental analysis the default behavior for docimp analyze

[nikblanchet]

Summary

Make incremental analysis the default behavior for docimp analyze to improve performance and user experience without requiring users to remember the --incremental flag.

Current Behavior

Users must explicitly use the --incremental flag to benefit from faster incremental analysis:

docimp analyze ./src --incremental

This requires users to:

• Know the feature exists
• Remember they ran analysis before
• Manually add the flag each time
• Understand when it will help

Proposed Behavior

Auto-detect and use incremental mode by default:

docimp analyze ./src
# Automatically detects previous analysis
# Uses incremental mode if applicable
# Shows message explaining what happened

User-facing message:

Analysis complete

I noticed you had previously run analysis on this codebase. To improve performance, 
I only re-analyzed the 3 files that changed (97 files reused from previous analysis).

If you want to force a complete re-analysis, run:
  docimp analyze --force-full-analysis ./src

Time saved: ~27 seconds (90% faster)

Implementation Details

Changes Required

1. Auto-detection logic in analyzeCore():

   • Check for previous analysis in .docimp/session-reports/analyze-latest.json
   • Check for workflow state in .docimp/workflow-state.json
   • If both exist, automatically use incremental mode

2. New flag: --force-full-analysis (or --no-incremental):

   • Overrides auto-incremental behavior
   • Forces full analysis of all files
   • Useful for benchmarking or debugging

3. Keep --incremental for backwards compatibility:

   • Make it a no-op (incremental is now default)
   • Update documentation to note it's redundant
   • Keep for users who like being explicit

4. Enhanced messaging:

   • Show when incremental mode was used
   • Display file counts (changed vs reused)
   • Show estimated time savings
   • Provide clear opt-out instructions

Files to Modify

• cli/src/commands/analyze.ts - Auto-detection logic
• cli/src/index.ts - Add --force-full-analysis flag, document --incremental as redundant
• cli/src/display/terminal-display.ts - Enhanced analysis result messaging
• CLAUDE.md - Update documentation
• README.md - Update user-facing docs

Benefits

• Better UX: Optimal performance without cognitive load
• Education: Users learn about incremental analysis through messages
• Backwards compatible: Existing --incremental usage still works
• Discoverable: Users see performance improvements automatically

Related

• Issue Add --dry-run flag for incremental analysis preview #376: --dry-run flag for incremental analysis
• Workflow State Management: docs/patterns/workflow-state-management.md
• Performance benchmarks show 90-95% time savings for typical incremental runs

Priority

High - This significantly improves UX for all users with minimal implementation effort. Makes a powerful feature accessible without requiring flag knowledge.