cleanup(dashboard): remove dead CSS selectors

Four selectors defined in dashboard.css but referenced nowhere in the
repo (verified against all html/js/rs, including dynamically-built class
names):

- .role-m1nd / .role-ag3nt — old per-role colouring; only `.role-pending`
  is still applied (`'role role-pending'`), and there's no `'role-' +`
  builder, so the m1nd/ag3nt variants are unreachable.
- .journal-body — the journald viewer is now a link to the dedicated
  logs.html page (`menuLink('journal logs →', …)`), not an inline panel.
- .talkform (+ its select/input/placeholder/focus rules) — old operator
  T4LK form styling, no longer emitted.

Part of #1450. Pure dead-code removal, no behaviour change; dashboard
bundle still builds (dashboard.css 36.9kb → 36.1kb).

frontend/packages/dashboard/src/dashboard.css

@@ -241,8 +241,6 @@ body.dashboard-shell {
   letter-spacing: 0.1em;
   text-transform: uppercase;
 }
-.role-m1nd { color: var(--pink); border-color: var(--pink); background: rgba(245, 194, 231, 0.08); }
-.role-ag3nt { color: var(--amber); border-color: var(--amber); background: rgba(250, 179, 135, 0.08); }
 
 /* Container rows: a full-height square agent icon on the left, the
    identity / actions / drill-in lines stacked in the card body on the
@@ -508,16 +506,6 @@ body.dashboard-shell {
 }
 .container-row.tombstone .name { color: var(--muted); }
 
-/* Per-container journald viewer + applied-config viewer in the side
-   panel. The panel-body wrapper fills the height with a column flex
-   so the <pre> can grow into a single scrollable surface. */
-.journal-body {
-  display: flex;
-  flex-direction: column;
-  height: 100%;
-  gap: 0.4em;
-}
-
 /* Notification controls — sit between the banner and the containers. */
 .port-conflict {
   background: rgba(243, 139, 168, 0.08);
@@ -881,24 +869,6 @@ ul form.inline { display: inline-block; }
   color: var(--amber);
 }
 @keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }
-.talkform {
-  display: flex;
-  gap: 0.6em;
-  align-items: stretch;
-  margin-top: 0.5em;
-}
-.talkform select, .talkform input {
-  font-family: inherit;
-  font-size: 1em;
-  background: var(--bg-elev);
-  color: var(--fg);
-  border: 1px solid var(--border);
-  padding: 0.4em 0.6em;
-}
-.talkform select { color: var(--amber); }
-.talkform input { flex: 1; }
-.talkform input::placeholder { color: var(--muted); }
-.talkform input:focus, .talkform select:focus { outline: 1px solid var(--purple); }
 details { margin-top: 0.5em; }
 summary {
   cursor: pointer;