[FEATURE] Add clear button (X) in search input

[ascender1729]

Description

Add an X button inside the search input to quickly clear the current search text.

Why Needed

• Faster than selecting all + delete
• Standard input pattern
• Improves mobile usability

Implementation Details

• Show X button only when input has text
• Position inside input on the right
• Clear input and optionally reset results
• Focus remains in input after clear

Files to Modify

• src/components/results/ResultsContainer.svelte

Code Example

<div class="relative">
  <input bind:value={searchQuery} />
  {#if searchQuery}
    <button 
      onclick={() => searchQuery = ''}
      class="absolute right-2 top-1/2 -translate-y-1/2"
      aria-label="Clear search"
    >
      <XIcon />
    </button>
  {/if}
</div>

Acceptance Criteria

• X button appears when input has text
• Hidden when input is empty
• Clears input on click
• Keyboard accessible

Time Estimates

• With AI: 135 minutes
• Without AI: 900 minutes