debate-pathology: prompt-engineering uplift (#26, follow-up to v0.13.0)

Applies the uplift template to all six Groupthink / Polarization /
Contagion prompts.

Debate-Pathology-specific additions:

- DEBATE_SYSTEM_PROMPT now ships the three-pathology distinction as
  a load-bearing rule:
    * rapid agreement WITHOUT extremity escalation -> groupthink
    * extremity escalation WITH visible disagreement -> polarization
    * tone-driven shifts INDEPENDENT of content -> contagion
  This prevents the common LLM failure of scoring all three the same.
- Per-pathology symptom signatures spelled out (Janis 1972 for
  illusion-of-unanimity; Stoner 1968 + Sunstein 2002 for risky-shift;
  Hatfield/Cacioppo/Rapson 1993 for emotional cascade).
- PATHOLOGY_SCORING_PROMPT one-shot demonstrates classic groupthink
  with verbatim "we already decided this, let's move on" evidence
  and a Janis 1972 anchor.
- Four-band score calibration maps directly to the four-label
  severity wire format.
- Canonical pathology order enforced (groupthink, polarization,
  contagion).
- FORENSIC_CONVERGENCE_TIMELINE_PROMPT now excludes procedural
  agreement (turn order, format) from convergence counting; this
  was a common false-positive in v0.12.x.

Wire format unchanged. All 45 Debate Pathology tests + 84 diagnose
tests still pass.

Author: valani9