Reject coerced and out-of-range skip_on_away values

Review remediation for PR #194:
- Admin create/edit request models use StrictBool so JSON 0/1 and
  "true"/"false" are 422 instead of being coerced to a bool.
- Fresh-schema quest_definitions gains CHECK (skip_on_away IN (0, 1));
  migrated databases (column added without the CHECK) are guarded by a
  DAO validator applied at every write path that takes the flag.
- QuestDefinitionsDao.update() accepts skip_on_away (None leaves it
  unchanged), validated like the other write paths.

Task: ded75ab8-0219-4d52-aefa-82c09e0b5e6b

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/routes_admin.py

@@ -251,7 +251,7 @@ import datetime
 from typing import Annotated, Literal, NoReturn
 
 from fastapi import APIRouter, Depends, HTTPException, Request, Response
-from pydantic import BaseModel, field_validator, model_validator
+from pydantic import BaseModel, StrictBool, field_validator, model_validator
 
 from api import transitions as api_transitions
 from api.auth import require_admin
@@ -464,7 +464,7 @@ class AdminQuestDefinitionCreateRequest(BaseModel):
     windows: list[str | tuple[str, str | None]]
     description: str | None = None
     icon: str | None = None
-    skip_on_away: bool = True
+    skip_on_away: StrictBool = True
 
 
 class AdminQuestDefinitionEditRequest(BaseModel):
@@ -488,7 +488,7 @@ class AdminQuestDefinitionEditRequest(BaseModel):
     icon: str | None = None
     rule: AdminRuleRequest | None = None
     windows: list[str | tuple[str, str | None]] | None = None
-    skip_on_away: bool | None = None
+    skip_on_away: StrictBool | None = None
 
 
 class AdminQuestDefinitionActiveRequest(BaseModel):