feat: ritual + judgment + favor + cross-over (Workstream B)

Implements Workstream B of the character-depth-ghost-log spec:
ritual_start/ritual_step/judgment WS handlers, the pure judgment.py
logic module, and the User.favor / Entity.at_peace columns + migration.

- app/judgment.py: pure ritual success roll (base 65%, floored at 30%,
  driven by an entity's power+deceptiveness difficulty), the "stuck
  spirit" cross_over rule (alignment >= 0.5 and volatility > 0.6, ~20%
  of entities), judgment correctness/favor-delta/essence-delta/
  consequence resolution for all four verdicts, favor clamping, the
  favor-to-trait-roll bias applied at mint time, and tell-line
  generation (opaque behavioral flavor text, never a raw stat).
- app/ws.py: wires ritual_start/ritual_step/judgment frames, emits
  ritual_complete/tell/judgment_result/item_drop per the spec's
  Contract; traits are added to serialize_entity for internal
  server-side use but stripped from the outbound `entity` frame via a
  new _public_entity helper so hidden ground truth never reaches the
  client outside ritual_complete; _summon excludes at-peace entities
  from signature re-contact and mints a fresh (salted-signature) entity
  instead; new entities' traits are nudged by the discovering user's
  favor before being persisted.
- models/user.py, models/entity.py, main.py: User.favor and
  Entity.at_peace columns plus their idempotent ADD COLUMN IF NOT
  EXISTS migration lines in lifespan, alongside the existing ones.
- tests/test_judgment.py, tests/test_ws_ritual_judgment.py: 56 new
  tests covering the ritual/judgment correctness matrix, favor
  clamping/bias, essence crediting, at_peace persistence + re-contact,
  and the entity-frame trait leak guard.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/models/entity.py

@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime, timezone
 
-from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.orm import Mapped, mapped_column
 
@@ -27,6 +27,12 @@ class Entity(Base):
     traits: Mapped[dict] = mapped_column(JSONB, default=dict)
     sample_quotes: Mapped[list] = mapped_column(JSONB, default=list)
     contact_count: Mapped[int] = mapped_column(Integer, default=0)
+    # Workstream B (character-depth-ghost-log spec): set true when a seeker
+    # correctly helps a genuinely benevolent, "stuck" spirit cross over. The
+    # row is never deleted (memorialized in the Codex permanently) but
+    # `signature_from_anomalies` re-contact in app.ws._summon skips it and
+    # mints a fresh entity instead.
+    at_peace: Mapped[bool] = mapped_column(Boolean, default=False)
     discovered_by: Mapped[uuid.UUID | None] = mapped_column(
         ForeignKey("users.id"), nullable=True
     )