Admin settings: give each ingestion source its own card

The sources panel (Telegram/Bale/Divar/Medjobs/Websites/Proxy) ran
together as one flat list. Each is now wrapped in a bordered .source-box
with an icon + hint, so it's clear where one source's settings end and the
next begins.

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

src/JobsMedical.Web/wwwroot/css/site.css

@@ -376,6 +376,11 @@ label { font-size: 13px; }
 @keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }
 .settings-panel h3:first-child { margin-top: 0; }
 
+/* Each ingestion source gets its own card so the settings don't run together. */
+.source-box { border: 1px solid var(--line); border-radius: 14px; padding: 14px; margin: 12px 0; background: var(--surface); }
+.source-box .toggle-row { background: var(--bg); margin-bottom: 10px; }
+.source-box .filter-group:last-child { margin-bottom: 0; }
+
 /* Toggle rows — give each boolean field a clean, card-like row. */
 .toggle-row {
   display: flex; align-items: flex-start; gap: 10px; font-weight: 700;