Show per-PC credentials across the admin interface

- Endpoints (shared key) page: the key is presented as what PCs use until
  they enroll, with enrollment progress, a link to Enrollment, rewritten
  guidance, and rotate/revoke confirmations that say how many PCs are not
  enrolled yet.
- Settings cards describe the server certificate as what PCs actually
  receive, on IIS or Docker; Enrollment has its own icon (the icon set lacked
  the one the Server Certificate card already asked for).
- Server Certificate page checks the certificate the site presents at its
  public address and compares its pin with the certificate file, warning when
  they differ. The host comes from site settings only; the check is a TLS
  handshake, never an HTTP request.
- Fleet list: Credential column and filter (enrolled, pending, re-enroll
  blocked, shared key, not reporting), computed in the list query.
- PC detail: credential state, prefix and dates for fleet readers, state only
  for others, with admin Revoke (optionally blocking re-enrollment) and Allow
  re-enrollment.
- Dashboard: pending enrollment requests, and PCs blocked from re-enrolling
  for more than seven days.
- Runbook: where to find each of these in the app.

plugins/endpoints/plugin.py

@@ -341,8 +341,9 @@ class EndpointsPlugin(BasePlugin):
                 'to': '/settings/endpoints/agentkey',
                 'icon': 'key',
                 'title': 'Endpoints',
-                'description': 'Manage the endpoint agent key, build the site '
-                               'agent, and configure what it reports.',
+                'description': 'The shared agent key PCs use until they '
+                               'enroll, the site agent installer builder, and '
+                               'what the agent reports.',
                 'position': 27,
             },
             # Its own card rather than a section of the agent key page: the
@@ -365,15 +366,15 @@ class EndpointsPlugin(BasePlugin):
                 'to': '/settings/endpoints/server-cert',
                 'icon': 'shield-check',
                 'title': 'Server Certificate',
-                'description': 'Manage the TLS certificate nginx uses for HTTPS. '
-                               'Agents validate this certificate via pinning or '
-                               'Windows trusted roots.',
+                'description': 'The certificate PCs see when they connect, on '
+                               'IIS or Docker. Source of the server pin and the '
+                               'trusted root entry for agents.',
                 'position': 29,
             },
             {
                 'group': 'Endpoints',
                 'to': '/settings/endpoints/enrollment',
-                'icon': 'key',
+                'icon': 'badge-check',
                 'title': 'Enrollment',
                 'description': 'Move agents to per-PC credentials, approve '
                                'enrollment requests, and retire the shared key.',
@@ -828,6 +829,46 @@ class EndpointsPlugin(BasePlugin):
                     'link': '/pcs/{computerid}',
                 },
             },
+            # One row, not one per PC: the approval itself happens on the
+            # Enrollment page, where the asset picker is.
+            {
+                'id': 'endpoints-enrollment-pending',
+                'viewall': '/settings/endpoints/enrollment',
+                'title': 'Enrollment requests waiting for approval',
+                'shortname': 'Enrollment',
+                'endpoint': '/api/endpoints/dashboard/enrollmentpending',
+                'render': 'exceptions',
+                'severity': 'warning',
+                'permission': 'endpoints.fleet',
+                'empty': 'hide',
+                'position': 24,
+                'map': {
+                    'title': 'summary',
+                    'detail': '',
+                    'link': '/settings/endpoints/enrollment',
+                },
+            },
+            # Info, not the queue: a block is deliberate (a rollback), and a
+            # week is only the point where it may have been forgotten.
+            {
+                'id': 'endpoints-reenroll-blocked',
+                'viewall': '/settings/endpoints/enrollment',
+                'title': 'PCs blocked from re-enrolling over 7 days',
+                'shortname': 'Re-enroll blocked',
+                'endpoint': '/api/endpoints/dashboard/reenrollblocked',
+                'render': 'exceptions',
+                'severity': 'info',
+                'permission': 'endpoints.fleet',
+                'empty': 'hide',
+                'position': 60,
+                'map': {
+                    'title': 'hostname',
+                    'detail': 'reason',
+                    'meta': [{'key': 'blockeddays', 'label': 'blocked',
+                              'suffix': ' days'}],
+                    'link': '/pcs/{computerid}',
+                },
+            },
         ]
 
     # ---- ADR-006 collector contract -------------------------------------