chore(web_ui): strip zero-width space from multiturn_composer comment

Stray U+200B (zero-width space) between "disables/" and "spinners" in a
comment tripped eslint no-irregular-whitespace. Likely a paste artifact
from Leonard's recent commit; fixed in passing during the merge.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: chiang-daniel

app/web_ui/src/lib/ui/conversation/multiturn_composer.svelte

@@ -194,7 +194,7 @@
        collapse via an empty-conditional slot without regressing append-mode
        layout (full-width button vs. fork-mode's right-aligned button next
        to Cancel). The cancel-button markup is the only difference. While
-       submitting, FormContainer disables/​spinners the Send button and we
+       submitting, FormContainer disables/spinners the Send button and we
        disable the textarea — the area stays put rather than being hidden. -->
   {#if mode === "fork" && on_cancel}
     <FormContainer