fix(rules): condition durations scale with caster level (hold person, doom, touch of fatigue, vanish)

ConditionEffect gains duration_rounds_per_level and max_duration_rounds
(mirroring PenaltyEffect), applied as caster_level * per_level rounds capped
at max: hold person 1 rd/lvl, doom 1 min/lvl, touch of fatigue 1 rd/lvl,
vanish 1 rd/lvl (max 5). Extend Spell doubles both the per-level rate and
the cap. Tests cover scaling and the vanish cap.

data/spells/doom.json

@@ -11,8 +11,9 @@
       "type": "condition",
       "condition_name": "shaken",
       "duration_rounds": 10,
+      "duration_rounds_per_level": 10,
       "save_negates": true
     }
   ],
-  "description": "SRD spells/doom.md: the subject is filled with horrible dread and becomes shaken (-2 on attacks and saves). Saving Throw Will negates - there is no partial success (the earlier '-1 on a successful save' wording was a D&D 3.5 rule that does not exist in PF1e). Duration 1 min/level approximated as 10 rounds."
+  "description": "SRD spells/doom.md: the subject is filled with horrible dread and becomes shaken (-2 on attacks and saves). Saving Throw Will negates - there is no partial success (the earlier '-1 on a successful save' wording was a D&D 3.5 rule that does not exist in PF1e). Duration 1 min/level (10 rounds per level)."
 }