"Score plateaued at X for N scans" message stays constant even when the score actually moves

[Vuk97]

desloppify version: 0.9.15
Severity: misleading status message

Bug

After every scan, the agent-plan output includes a "current status" line that reports a plateau number, e.g.:

Current status: ⚠ ... Score plateaued at 94.5 for 5 scans. File health (68.2%) is where the breakthrough is.

This message persists across scans EVEN IF the strict score has changed since the plateau was first detected. In one session I saw "Score plateaued at 94.5 for 5 scans" while the actual score had moved to 95.8 — a 1.3-point improvement that the plateau message ignored.

Steps to reproduce

$ desloppify scan --path . --force-rescan ...  # score: 95.8
  ...
  Score plateaued at 94.5 for 5 scans. File health is where the breakthrough is.
Strict score:    95.8/100      ← actual is 95.8, plateau message says 94.5

Expected behavior

The plateau message should either:

1. Update the plateau number when the strict score moves by more than a tolerance (e.g. ≥0.2 pts).
2. Reset the plateau counter on every score change.
3. Suppress the plateau message until N consecutive scans with the same exact score.

Impact

Minor but corrosive to trust. The user sees their score actively moving but the "plateaued at X" message implies they're stuck — leading to wasted decision-making (e.g. attempting a risky refactor that wasn't needed because the score was already moving).