J3 D8-d-fix: caster AC floor + HP ×1.25

computeAC: lift caster floors (cleric/druid 3→5, bard/warlock 1→3,
mage/sorcerer 0→2). Ranger 3 / rogue 1 / fighter+paladin 6 unchanged.

computeMaxHP: new casterHPMult(class) = 1.25 for the same caster set,
applied multiplicatively on top of phase5BHPMult. Martials unchanged.
New caster L10 HPMax: mage/sorc ~98 (was 78), bard/cleric/druid/warlock
~118 (was 95); martial L10 ~141 unchanged.

bootstrap_caster_hp.go: new bootstrapCasterHPRefresh (job key
caster_hp_refresh_v1) refreshes existing rows once at startup; mirrors
bootstrapPhase5BHPRefresh — only raises HPMax, preserves absolute
wound. Wired in adventure.go.

Measured on n=2500 d8dfix2 corpus (gitignored sim_results) vs d8c:
- T3 manor caster lift confirmed — bard +13 (43→56), druid +8 (88→96),
  warlock +8, sorcerer +5, mage +5, cleric +2. Martials flat.
- Macro deltas: bard +2.6, warlock +2.0, druid +1.4, mage/sorcerer +1.0,
  cleric -0.2. n=500 1σ ≈ 2.2pp — bard/warlock cleanly past noise.
- T4 underdark wall still holds (every caster ~0%). Lift directionally
  correct but undersized for T4 atk-bonus + multiattack — separate
  follow-up.
- T5 dragons_lair universal wall unchanged (martials TPK too).

Diagnostic context: project_d8d_diagnostic. Cleric flat manor likely
the concentration AOE re-tick engine gap (filed for D8-e+).

internal/plugin/adventure.go

@@ -220,6 +220,10 @@ func (p *AdventurePlugin) Init() error {
 	// migration walks dnd_character once at startup; idempotent via
 	// JobCompleted gate.
 	bootstrapPhase5BHPRefresh()
+	// J3 D8-d-fix: caster HP lift (casterHPMult in dnd.go). Refresh
+	// existing caster rows once at startup so the lift reaches live
+	// players without waiting for level-up.
+	bootstrapCasterHPRefresh()
 	// Phase R1 orphan-archive used to run here on every Init, but it
 	// over-archived: it treats any active dnd_zone_run row not linked to
 	// an active expedition as a legacy `!adventure dungeon` orphan, which