ui: tighten extra-labels padding to fit the actual key length

The Extra labels pre-block used padEnd(18) — a fixed width copied from
the main-labels block where it makes columns line up with header /
follower entries. In the extras block there's typically just one entry
(framework_args, 14 chars), so the fixed pad inserts 4 extra spaces
between key and value with nothing to align them to. Reads like a
formatting bug.

Compute the pad from the actual keys present + 1. With framework_args
alone, that's padEnd(15) — one space between key and value. If more
labels show up later, they self-align.

Author: robmsmt

frontend/src/components/ui/ModelCard.svelte

@@ -272,8 +272,9 @@
               !["launched_by","slurm_job_id","worker_group_id","framework","started_at","expires_at","slurm_partition","served_model_name"].includes(k)
             )}
             {#if extra.length > 0}
+              {@const pad = Math.max(...extra.map(([k]) => k.length)) + 1}
               <div class="text-xs text-slate-500 dark:text-slate-400 mt-2 mb-1">Extra labels</div>
-              <pre class="code-block">{extra.map(([k, v]) => `${k.padEnd(18)} ${v}`).join("\n")}</pre>
+              <pre class="code-block">{extra.map(([k, v]) => `${k.padEnd(pad)} ${v}`).join("\n")}</pre>
             {/if}
           {/if}
         </div>