enhancement: surface ReassemblyStats in reporter output

[Zious11]

Summary

Found by silent-failure-hunter during PR #37 review. The reassembly engine tracks detailed stats (segments_inserted, segments_duplicates, segments_overlaps, segments_out_of_window, segments_segment_limit, bytes_reassembled, evictions, etc.) but none of these are surfaced in the terminal or JSON reporter output.

Problem

ReassemblyStats is accessible via reassembler.stats() and used in tests, but the reporting pipeline only receives Summary, Vec<Finding>, and Vec<AnalysisSummary>. No code path passes reassembly stats to the reporters.

This means counters like segments_segment_limit (added in PR #37) and segments_out_of_window are invisible to users running wirerust analyze.

Recommended Fix

Two options (not mutually exclusive):

1. Add a reassembly stats section to reporter output — pass ReassemblyStats to TerminalReporter and JsonReporter, render as a summary section
2. Generate Findings for notable events — when segments_segment_limit > 0, segments_out_of_window > 0, or evictions > 0, generate a Finding during finalize() so users see these in the findings list (which IS surfaced)

Option 2 is lower effort and fits the existing pattern (overlap/small-segment anomalies already generate Findings).