Fixes batch 2: player quests, AI parse, advisor, iPad share

- Player view: a Quest log now syncs to players (snapshot += quests; broadcaster
  passes campaign quests; PlayerBoards renders titles + objective checkboxes).
- AI (DeepSeek etc.): robust JSON extraction — strip code fences anywhere + a
  brace-balanced scanner that ignores prose/braces in strings. Fixes "AI unavailable
  (parse)" with OpenAI-compatible providers. +4 tests.
- Encounter advisor: now bidirectional — for an over-tuned (too-hard) fight it
  suggests REMOVING/swapping monsters instead of only ever adding. +3 tests.
- Character share: works on iPad — native share sheet → clipboard → a copyable
  link modal fallback (was a silently-failing clipboard write).

230 unit + 34 e2e + 2 realtime green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/assistant/prompts.ts

@@ -9,6 +9,11 @@ export const balanceSuggestionSchema = z.object({
     count: z.number().int().min(1).max(8),
     ref: z.string().optional(),
   })),
+  /** Monsters to take out when the fight is over-tuned (already at/above target). */
+  remove: z.array(z.object({
+    name: z.string(),
+    count: z.number().int().min(1).max(8),
+  })).optional(),
   targetDifficulty: z.string(),
 });
 export type BalanceSuggestion = z.infer<typeof balanceSuggestionSchema>;