style(web): fix prettier config, format entire web/ tree

.prettierrc.json was missing "semi": false, so prettier wanted to add
semicolons to a codebase written without them (763 semicolon-free
statements vs. 150 with, in hand-written .ts; zero hand-written .svelte
files use them at all). That's why prettier --check failed on 249 files
— not because the code was unformatted, but because the config didn't
match the actual house style. Added "semi": false; left printWidth/etc
as configured (printWidth barely moves the failure count: 218/213/212
files at 100/120/140).

Ran `prettier --write .` with the corrected config. Verified
semantics-preserving before and after:
- eslint: 142 problems both before and after, byte-identical
- build passes, 38/38 tests pass
- token-stream diff (whitespace/semicolons/quotes normalized) on all
  218 changed files: only 52 had any remaining token change, all either
  trailing-comma removal (matching trailingComma: "none") or import/
  ternary reflow — no semantic changes
- live smoke test: Knowledge, Tasks, Fleet map, and a chat window
  (AgentTrace, markdown, Scope graph, activity rail) all render
  correctly, no console errors

Most of the diff is shadcn/ui vendor files (lib/components/ui/) moving
from the CLI's own style (double quotes, tabs, semicolons) to house
style; re-running `shadcn-svelte add` on a component will need a
follow-up format pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/lib/components/desktop-shell/DesktopIcon.svelte

@@ -88,10 +88,14 @@
   onkeydown={onKeydown}
   title={app.title}
 >
-  <span class="relative flex size-10 items-center justify-center rounded-xl border bg-card/80 text-foreground shadow-sm backdrop-blur">
+  <span
+    class="relative flex size-10 items-center justify-center rounded-xl border bg-card/80 text-foreground shadow-sm backdrop-blur"
+  >
     <app.icon class="size-5" />
     {#if badge > 0}
-      <span class="absolute -right-1.5 -top-1.5 flex h-4 min-w-4 items-center justify-center rounded-full bg-destructive px-1 text-[10px] font-semibold text-destructive-foreground">
+      <span
+        class="absolute -right-1.5 -top-1.5 flex h-4 min-w-4 items-center justify-center rounded-full bg-destructive px-1 text-[10px] font-semibold text-destructive-foreground"
+      >
         {badge > 99 ? '99+' : badge}
       </span>
     {/if}