feat(role-editor): "Use as template" — copy another role's perm set

Adds a select+button next to the permission editor: pick any other role
from the dropdown, click "Use as template" → all checkboxes are replaced
with that role's permission set. Local-only (no API call); the user still
hits "Save changes" to persist. Includes a banner confirming the load
with the source role name + perm count.

Selector excludes the currently-edited role. Hidden for non-admins.

UI: dark card row matching the Foundry Deck token system (--bg-card,
--text-dim mono label, --bg-sink select with --accent focus border).

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

src/index.css

@@ -663,6 +663,32 @@ dd { font-size: .92rem; font-family: 'JetBrains Mono', monospace; }
   color: var(--text-dim); font-size: .72rem; line-height: 1.35; margin-top: 2px;
 }
 
+.role-editor-template {
+  display: flex; align-items: center; gap: 10px;
+  background: var(--bg-card); border: var(--hair); border-radius: var(--radius);
+  padding: 10px 14px; margin-bottom: 14px;
+  font-size: .82rem;
+}
+.role-editor-template label {
+  color: var(--text-dim); text-transform: uppercase;
+  letter-spacing: .12em; font-size: .72rem;
+  font-family: 'JetBrains Mono', monospace;
+  white-space: nowrap;
+}
+.role-editor-template select {
+  flex: 1; min-width: 0;
+  padding: 7px 10px;
+  background: var(--bg-sink); color: var(--text);
+  border: var(--hair); border-radius: var(--radius);
+  font-family: 'JetBrains Mono', monospace; font-size: .82rem;
+  cursor: pointer; transition: .12s;
+}
+.role-editor-template select:hover  { border-color: var(--border-bright); }
+.role-editor-template select:focus  { border-color: var(--accent); outline: none; }
+.role-editor-template button:disabled {
+  opacity: .4; cursor: not-allowed; border-color: var(--border);
+}
+
 .role-editor-actions {
   display: flex; gap: 10px; margin-top: 22px;
   padding-top: 18px; border-top: var(--hair);

src/pages/RoleEditorPage.tsx

@@ -30,6 +30,7 @@ export default function RoleEditorPage() {
   const [newRoleName, setNewRoleName] = useState('')
   const [newRoleDesc, setNewRoleDesc] = useState('')
   const [creating, setCreating] = useState(false)
+  const [templateRoleId, setTemplateRoleId] = useState<string>('')
 
   const isAdmin = user?.is_admin === true
 
@@ -58,6 +59,20 @@ export default function RoleEditorPage() {
     setSelectedRole({ ...selectedRole, permission_ids: newPermIds })
   }
 
+  // Copy a source role's permission_ids over the current selection.
+  // Replaces (not merges) — the user explicitly clicked "use as template".
+  // Local-only: nothing persists until they hit "Save changes".
+  const handleApplyTemplate = () => {
+    if (!selectedRole || !templateRoleId) return
+    const src = roles.find((r) => String(r.id) === templateRoleId)
+    if (!src) return
+    setSelectedRole({ ...selectedRole, permission_ids: [...src.permission_ids] })
+    flashMessage(
+      `Loaded ${src.permission_ids.length} permissions from "${src.name}" — not saved yet`,
+      true,
+    )
+  }
+
   const flashMessage = (msg: string, ok: boolean) => {
     setMessage(msg); setMessageOk(ok)
   }
@@ -206,6 +221,35 @@ export default function RoleEditorPage() {
           {selectedRole ? (
             <>
               <h3>Permissions for <span className="name">{selectedRole.name}</span></h3>
+
+              {isAdmin && roles.length > 1 && (
+                <div className="role-editor-template">
+                  <label htmlFor="tpl-select">Copy from template:</label>
+                  <select
+                    id="tpl-select"
+                    value={templateRoleId}
+                    onChange={(e) => setTemplateRoleId(e.target.value)}
+                  >
+                    <option value="">— select a role —</option>
+                    {roles
+                      .filter((r) => r.id !== selectedRole.id)
+                      .map((r) => (
+                        <option key={r.id} value={r.id}>
+                          {r.name} ({r.permission_ids.length} perms)
+                        </option>
+                      ))}
+                  </select>
+                  <button
+                    className="btn-secondary"
+                    disabled={!templateRoleId}
+                    onClick={handleApplyTemplate}
+                    title="Replace current checkboxes with the template role's permission set (local; not saved until you click Save changes)"
+                  >
+                    Use as template
+                  </button>
+                </div>
+              )}
+
               {Object.entries(groupedPermissions).map(([category, perms]) => (
                 <div key={category} className="perm-group">
                   <div className="perm-group-header">{category}</div>