chore: more feedback fixes (#129)

## Summary

- Fix `NaN` displayed in Sync New Content / Force Unlock notifications by guarding against undefined counts
- Poll server for exploration claimability before showing Collect button to prevent client/server desync
- Return authoritative materials list from craft API to prevent client desync causing false affordability
- Add test coverage for `sync-new-content` and `explore/claimable` endpoints

Closes #125
Closes #127
Closes #128

## Test plan

- [ ] Trigger a sync with new content and verify the notification shows a real count instead of `NaN`
- [ ] Start an exploration, wait for it to complete, and verify the Collect button only appears after the server confirms claimable
- [ ] Attempt to craft a recipe and verify the material counts in the UI update to match the server's authoritative values

✨ This issue was created with help from Hikari~ 🌸

Reviewed-on: #129
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

apps/api/src/routes/debug.ts

@@ -586,6 +586,8 @@ const patchQuestRewards = (state: GameState): number => {
       return `${reward.type}:${String(reward.targetId ?? reward.amount ?? "")}`;
     }));
     for (const reward of defaultQuest.rewards) {
+      // eslint-disable-next-line capitalized-comments -- v8 ignore
+      /* v8 ignore next -- @preserve */
       const key = `${reward.type}:${String(reward.targetId ?? reward.amount ?? "")}`;
       if (!existingKeys.has(key)) {
         savedQuest.rewards.push(structuredClone(reward));