feat: Global-Admin Org-Switcher fuer info@aegis-sight.de

Ermoeglicht dem Global Admin (is_global_admin Flag) zwischen
Organisationen zu wechseln. Neue Endpoints: GET /api/auth/organizations,
POST /api/auth/switch-org. Org-Dropdown im Header-Menue, nur fuer
Global Admin sichtbar. Komplett herausnehmbar (Flag + Code-Bloecke).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/static/css/style.css

@@ -5445,3 +5445,41 @@ body.tutorial-active .tutorial-cursor {
     font-size: 11px;
     color: var(--text-tertiary);
 }
+
+/* --- Global Admin: Org-Switcher (herausnehmbar) --- */
+.org-switcher-section {
+    padding: 0;
+    text-align: left;
+}
+
+.org-switcher-label {
+    font-size: 11px;
+    font-weight: 600;
+    letter-spacing: 0.5px;
+    color: var(--text-tertiary);
+    text-transform: uppercase;
+    margin-bottom: 6px;
+    display: block;
+}
+
+.org-switcher-select {
+    width: 100%;
+    padding: 6px 8px;
+    font-size: 13px;
+    border-radius: 6px;
+    border: 1px solid var(--border);
+    background: var(--bg-secondary);
+    color: var(--text-primary);
+    cursor: pointer;
+    outline: none;
+    transition: border-color 0.15s;
+}
+
+.org-switcher-select:hover {
+    border-color: var(--accent);
+}
+
+.org-switcher-select:focus {
+    border-color: var(--accent);
+    box-shadow: 0 0 0 2px rgba(var(--accent-rgb, 59, 130, 246), 0.15);
+}