balance: rework mana economy, HP thresholds, spell costing, and shield-breakers

Combat-pacing rebalance to curb single-cast overcast greed and long-fight
stalemates without further nerfing base spell damage:

- Replace the per-round mana cap with a daily mana pool (old Poziom Mocy
  values x3), restored via rest tiers (Odetchniecie/Krotki/Dlugi Odpoczynek).
- Add a mundane-only "Kara za Wyczerpanie Many" table for casting past the
  daily pool, and a "Kara za Nieudolnosc" table for failed overcast tests -
  deliberately kept free of Otchlan/Obled corruption.
- Taper overcast effect bonuses past step 2 (halved, min 1) to blunt
  free-zone alpha strikes below Maksymalny Koszt Zaklecia.
- Rebalance Zywotnosc/Oszolomiony/rest-recovery from 3x/1-3 to 2x/1-2.
- Add a "Potega Efektu" magnitude parameter to the spell-costing formula,
  decoupling effect strength from casting difficulty (T/S).
- Flip the Obrazenia/Ochrona category modifiers (-0.4/+0.2, was 0.0/-0.7) so
  shields cost more than comparable attacks instead of less, then swept all
  spell files against the new formula.
- Expand shield-breaking beyond Ether Pierce (Mysterious Stream, Arrow of
  Desire, Energy Wave, Divine Spear, Last Judgment, True Disintegration),
  rework Forbidden Shield into a durability-based ward with a shield-ignoring
  counter-attack, and complete True Disintegration's description, which was
  truncated since the initial commit.
- Formalize the four-layer damage reduction order (Runiczny Pancerz ->
  Magiczna Oslona -> Pancerz -> Zywotnosc) in the rulebook.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019xsdbKAT27PoAX9SWH3MFK

spells/academic/earth-magic/quicksand.md

@@ -7,7 +7,7 @@ castingMode: standard
 school: elementsEarth
 deity: ''
 sourceBook: ksiega-magii
-manaCost: 3
+manaCost: 5
 bloodCost: 0
 complexityLevel: 3
 isSuperspell: false

spells/academic/earth-magic/stone-shield.md

@@ -39,7 +39,7 @@ range:
   kind: distance
   value: 5
   unit: m
-duration: 1 runda
+duration: 2 rundy
 castingTime: ''
 target: Nie dotyczy
 areaOfEffect: null

spells/academic/fire-magic/burning-skin.md

@@ -7,7 +7,7 @@ castingMode: standard
 school: elementsFire
 deity: ''
 sourceBook: ksiega-magii
-manaCost: 5
+manaCost: 2
 bloodCost: 0
 complexityLevel: 2
 isSuperspell: false