Add hospital revival, Robbie bandit, MW/shop fixes, float64 scoring

- St. Guildmore's Memorial Hospital: !hospital command with Nurse Joy,
  procedural itemized billing, same-day revival, 6-hour dead timer,
  hospital ad after death, 2-hour nudge follow-up
- Robbie the Friendly Bandit: automated inventory cleaner, random daily
  visits (8-21 UTC, 40% chance), collects sub-tier gear at €50/item,
  donates to community pot, drops Get Out of Medical Debt Free card
- Fix MW auto-equip: T1 MW no longer replaces better equipped gear
- Fix shop MW block: allow purchasing upgrades over lower-tier MW
- Float64 equipment scoring: advEffectiveTier and advEquipmentScore
  return float64, no mid-calculation truncation (MW 1.25x, Arena 1.5x)
- Fix markdown rendering: convert *asterisk* to _underscore_ italics
  across all flavor text files (shop, blacksmith, rival, hospital)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/db/db.go

@@ -79,6 +79,8 @@ func runMigrations(d *sql.DB) error {
 		`ALTER TABLE adventure_characters ADD COLUMN babysit_active INTEGER NOT NULL DEFAULT 0`,
 		`ALTER TABLE adventure_characters ADD COLUMN babysit_expires_at DATETIME`,
 		`ALTER TABLE adventure_characters ADD COLUMN babysit_skill_focus TEXT NOT NULL DEFAULT ''`,
+		`ALTER TABLE adventure_characters ADD COLUMN hospital_visits INTEGER NOT NULL DEFAULT 0`,
+		`ALTER TABLE adventure_characters ADD COLUMN robbie_visit_count INTEGER NOT NULL DEFAULT 0`,
 	}
 	for _, stmt := range columnMigrations {
 		if _, err := d.Exec(stmt); err != nil {