Add name/type=search to search inputs (autofill/a11y warning)

The room filter, message search, and channel-search inputs had neither
id nor name — browsers warn and can't autofill correctly. Give each a
name + type=search + autoComplete=off. Bump SW cache v12 -> v13.

public/sw.js

@@ -1,7 +1,7 @@
 // Tchatou service worker — installable PWA + offline app shell.
 // Scope: /app/. Only handles same-origin /app/ GETs; the IRC websocket and all
 // API calls (cloudflare, change_password, upload) pass straight through.
-const CACHE = 'tchatou-v12';
+const CACHE = 'tchatou-v13';
 const SHELL = ['/app/', '/app/index.html', '/app/favicon.svg', '/app/manifest.webmanifest'];
 
 self.addEventListener('install', (e) => {

src/components/chat/Sidebar.tsx

@@ -88,7 +88,7 @@ export function Sidebar({ onNavigate }: { onNavigate: () => void }) {
 
       <div className="side-search">
         <span className="side-search__icon">🔍</span>
-        <input value={q} onChange={(e) => setQ(e.target.value)} placeholder="Rechercher" aria-label="Rechercher" />
+        <input name="room-filter" type="search" autoComplete="off" value={q} onChange={(e) => setQ(e.target.value)} placeholder="Rechercher" aria-label="Rechercher" />
       </div>
 
       <div className="pills">

src/components/chat/Topbar.tsx

@@ -24,7 +24,7 @@ export function Topbar({ onMenu, onMembers }: { onMenu: () => void; onMembers: (
       <div className="topbar topbar--search">
         <button className="nav-toggle" onClick={onMenu} aria-label="Salons">☰</button>
         <span className="topbar__searchicon">🔍</span>
-        <input className="topbar__searchinput" autoFocus placeholder={`Rechercher dans ${label}…`}
+        <input className="topbar__searchinput" name="message-search" type="search" autoComplete="off" autoFocus placeholder={`Rechercher dans ${label}…`}
           value={search} onChange={(e) => setSearch(e.target.value)}
           onKeyDown={(e) => { if (e.key === 'Escape') { setSearch(''); setSearching(false); } }} />
         <button className="topbar__searchclose" onClick={() => { setSearch(''); setSearching(false); }} aria-label="Fermer la recherche">✕</button>

src/components/modals/Modals.tsx

@@ -78,7 +78,7 @@ function ExploreModal() {
   return (
     <Modal title="Explorer les salons" onClose={() => setModal('')}>
       <div className="set-inline" style={{ marginBottom: '.7rem' }}>
-        <input className="modal__input" placeholder="Rechercher ou créer #salon…" value={q}
+        <input className="modal__input" name="channel-search" type="search" autoComplete="off" placeholder="Rechercher ou créer #salon…" value={q}
           onChange={(e) => setQ(e.target.value)}
           onKeyDown={(e) => { if (e.key === 'Enter' && q.trim()) join(q); }} autoFocus />
         <button className="upbtn upbtn--primary" onClick={() => join(q)} disabled={!q.trim()}>Rejoindre</button>