fix: add null guards for uncapLevel usage

- UncapIndicator.svelte: Use nullish coalescing for uncapLevel comparison
- UncapStatusDisplay.svelte: Guard uncapLevel in badge active checks

Fixes "'uncapLevel' is possibly 'null'" errors.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/lib/components/sidebar/modifications/UncapStatusDisplay.svelte

@@ -86,10 +86,10 @@
       <span class="label">Available Upgrades</span>
       <div class="uncap-badges">
         {#if flb}
-          <span class="badge" class:active={uncapLevel >= 4}>FLB</span>
+          <span class="badge" class:active={(uncapLevel ?? 0) >= 4}>FLB</span>
         {/if}
         {#if ulb}
-          <span class="badge" class:active={uncapLevel >= 5}>ULB</span>
+          <span class="badge" class:active={(uncapLevel ?? 0) >= 5}>ULB</span>
         {/if}
         {#if transcendence}
           <span class="badge" class:active={transcendenceStep > 0}>Trans</span>

src/lib/components/uncap/UncapIndicator.svelte

@@ -91,7 +91,7 @@
 		return {
 			type: 'uncap',
 			props: {
-				empty: options.index >= uncapLevel,
+				empty: options.index >= (uncapLevel ?? 0),
 				index: options.index,
 				flb: options.flb,
 				ulb: options.ulb,