feat: session status at a glance, file & image drop, live Ops Alerts (0.4.0)

- devdesk-state-hook (Claude UserPromptSubmit/PostToolUse/Notification/Stop/
  SessionStart/SessionEnd) records whether each session is working, waiting on
  you or idle; --list carries it. The sidebar shows it, the header shows the
  current session's state, and a pulsing "needs you" chip jumps to sessions
  waiting for input. Session refresh no longer depends on the sidebar being open.
- `devdesk attach --upload SESSION FILE BYTES` receives a file as base64
  terminal input (raw mode, exact length, size-checked, sanitised name) into
  /var/lib/devdesk/uploads/<session>/. The UI uploads dropped or pasted files and
  pastes the path into Claude, which attaches images itself.
- `devdesk alerts` / `--alerts`: firing and pending Grafana alert rules with
  severity, instances, summary and a link. The panel's "Ask Claude" types an
  investigation prompt into the current session.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/styles.css

@@ -211,6 +211,24 @@ body.dd-sidebar-open .dd-sidebar {
 .dd-session-item.is-recent .dd-session-name { color: var(--text-secondary); font-weight: 400; }
 
 .dd-session-item.is-dormant .dd-session-name { color: var(--text-secondary); }
+.dd-session-item.is-waiting { border-color: rgba(255, 45, 85, 0.45); background: var(--accent-red-dim); }
+.dd-session-item.is-waiting .dd-session-meta { color: var(--accent-red); }
+.dd-session-item.is-working .dd-session-meta { color: var(--accent-amber); }
+
+/* Header chips: current session's Claude state, and sessions needing you. */
+.dd-state-chip { display: none; }
+.dd-state-chip[data-state="working"] { display: inline-flex; color: var(--accent-amber); background: var(--accent-amber-dim); }
+.dd-state-chip[data-state="waiting"] { display: inline-flex; color: var(--accent-red); background: var(--accent-red-dim); text-shadow: var(--glow-red); }
+.dd-state-chip[data-state="idle"] { display: inline-flex; color: var(--accent-green); background: var(--accent-green-dim); }
+.dd-attention {
+  display: none;
+  cursor: pointer;
+  font-family: var(--font-mono);
+  color: var(--accent-red);
+  background: var(--accent-red-dim);
+  animation: lt-pulse 1.6s ease-in-out infinite;
+}
+.dd-attention.is-active { display: inline-flex; }
 
 .dd-session-actions {
   display: flex;
@@ -275,24 +293,63 @@ body.dd-sidebar-open .dd-sidebar {
   gap: var(--space-sm);
 }
 
-/* ---- stub widgets ------------------------------------------------------------ */
+/* ---- ops alerts --------------------------------------------------------------- */
+.dd-alert-count { margin-left: auto; }
+.dd-alert-count:empty { display: none; }
+.dd-alert-list { display: flex; flex-direction: column; gap: var(--space-sm); }
 .dd-alert {
   display: flex;
-  align-items: center;
-  gap: var(--space-sm);
+  flex-direction: column;
+  gap: 3px;
+  padding: 6px 8px;
+  border: 1px solid var(--border-dim);
+  border-left: 2px solid var(--accent-amber);
   font-size: 0.72rem;
-  color: var(--text-secondary);
 }
-.dd-alert-text { flex: 1 1 auto; }
+.dd-alert:has(.lt-chip-critical) { border-left-color: var(--accent-red); }
+.dd-alert-head { display: flex; align-items: center; gap: var(--space-sm); min-width: 0; }
+.dd-alert-name { font-weight: 700; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.dd-alert-age { margin-left: auto; white-space: nowrap; }
+.dd-alert-instances { overflow-wrap: anywhere; }
+.dd-alert-summary { color: var(--text-secondary); }
+.dd-alert .dd-ask { align-self: flex-start; margin-top: 2px; }
+.dd-all-clear { display: flex; align-items: center; gap: var(--space-sm); color: var(--accent-green); font-size: 0.74rem; }
 
 .dd-context-grid { margin-top: var(--space-sm); }
 
-[data-state="stub"] .lt-section-body,
-#widget-context[data-state="empty"] .lt-kv-grid,
-#widget-repo[data-state="empty"] .lt-kv-grid { opacity: 0.6; }
+[data-state="stub"] .lt-section-body { opacity: 0.75; }
 
-.lt-status a { color: inherit; text-shadow: none; }
-.dd-widget .lt-kv-val { overflow-wrap: anywhere; }
+/* ---- file drop / upload ------------------------------------------------------ */
+.dd-drop-overlay {
+  position: absolute;
+  inset: 0;
+  z-index: 6;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  border: 2px dashed var(--accent-cyan);
+  background: rgba(0, 212, 255, 0.08);
+  color: var(--accent-cyan);
+  font-size: 0.9rem;
+  pointer-events: none;
+}
+.dd-drop-overlay[hidden] { display: none; }
+.dd-upload-status {
+  position: absolute;
+  right: 14px;
+  bottom: 16px;
+  z-index: 6;
+  max-width: 70%;
+  padding: 6px 10px;
+  border: 1px solid var(--accent-cyan-border);
+  background: var(--bg-secondary);
+  color: var(--text-secondary);
+  font-size: 0.72rem;
+  box-shadow: var(--box-glow-cyan);
+  overflow-wrap: anywhere;
+}
+.dd-upload-status[hidden] { display: none; }
+.dd-upload-status.is-error { border-color: rgba(255, 45, 85, 0.5); color: var(--accent-red); }
 
 /* ---- overlay ----------------------------------------------------------------- */
 .dd-overlay {