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/web/src/context/gameContext.tsx

@@ -1864,14 +1864,6 @@ export const GameProvider = ({
         if (previous?.exploration === undefined) {
           return previous;
         }
-        let materials = [ ...previous.exploration.materials ];
-        for (const request of recipe.requiredMaterials) {
-          materials = materials.map((mat) => {
-            return mat.materialId === request.materialId
-              ? { ...mat, quantity: mat.quantity - request.quantity }
-              : mat;
-          });
-        }
         return {
           ...previous,
           exploration: {
@@ -1884,7 +1876,7 @@ export const GameProvider = ({
               ...previous.exploration.craftedRecipeIds,
               recipeId,
             ],
-            materials: materials,
+            materials: result.materials,
           },
         };
       });