Split the fleet roster from per-endpoint reads, and stop offering controls nobody can use

Twelve endpoints routes shared one permission, which made a reasonable policy
impossible to express. A site that wants signed-out visitors to see live status
on a PC page had to hand them the entire fleet - including every logged-in
username on the floor - because the per-asset panels and the fleet-wide list
were gated on the same string.

endpoints.fleet now gates the list and the three dashboard routes.
endpoints.view keeps the per-asset reads: status, services, processes,
interfaces, events, command history.

The name is load-bearing. guest_grantable_permissions() opens any '.view' or
'.read' permission to the guest role, so calling this one 'endpoints.fleet'
rather than 'endpoints.fleetview' is what keeps the roster off the public
surface while per-asset telemetry stays grantable. Verified both ways.

Also: the services panel emitted Start/Stop row actions to every reader,
because row_actions_for() never consulted the caller. Clicking was always
refused server-side, so nothing was exploitable, but showing a read-only viewer
controls over a shop-floor PC is the wrong signal - and it stops being cosmetic
the moment a site grants that panel to guests.

That needed a contract addition rather than a local check: caller_holds() on
shopdb.api answers whether THIS caller holds a permission without refusing the
request, which is the complement to require_permission for a surface that
serves everyone but should only offer what the caller can act on. Guests are
included, since a signed-out visitor holds whatever the guest role was granted.
Reaching into shopdb.utils.authz instead would repeat the ADR-002 violation the
contract gate caught earlier in this branch. Contract 0.24.0 -> 0.25.0.

DEPLOYMENT: endpoints.fleet is a new permission. Run 'flask seed permissions'
and grant it to the roles that should keep seeing the Fleet page. Until then
that page is admin-only, since admins bypass every check - a safe direction,
but not an automatic one.

Full suite 2124 passed, naming and contract gates green, map and spec
regenerated.

plugins/endpoints/plugin.py

@@ -103,6 +103,22 @@ class EndpointsPlugin(BasePlugin):
         """
         return [
             ('endpoints.view', 'View endpoint telemetry', 'endpoints'),
+            # The FLEET-WIDE list and dashboards, separate from endpoints.view,
+            # which covers reading ONE endpoint that the caller already reached
+            # through its PC page.
+            #
+            # They were one permission, and that made a reasonable policy
+            # impossible to express: a site that wants signed-out visitors to
+            # see live status on a PC page had to hand them the whole fleet,
+            # including every logged-in username on the floor, because the
+            # panels and the list were gated on the same string.
+            #
+            # It is deliberately NOT named '.view'. guest_grantable_permissions
+            # opens any '.view' or '.read' permission to the guest role, so this
+            # name is what keeps the fleet roster off the public surface while
+            # per-asset telemetry can still be granted.
+            ('endpoints.fleet',
+             'View the fleet-wide endpoint list and dashboards', 'endpoints'),
             # Issue an allowlisted command to an endpoint agent (for example the
             # MTConnect toggle). Separate from endpoints.view because acting on a
             # shop-floor PC is a heavier grant than reading its telemetry.
@@ -189,7 +205,7 @@ class EndpointsPlugin(BasePlugin):
                 'icon': 'activity',
                 'route': '/endpoints',
                 'position': 16,
-                'permission': 'endpoints.view',
+                'permission': 'endpoints.fleet',
                 'section': 'assets',
             },
         ]
@@ -340,7 +356,7 @@ class EndpointsPlugin(BasePlugin):
                 'endpoint': '/api/endpoints/dashboard/quiet',
                 'render': 'exceptions',
                 'severity': 'warning',
-                'permission': 'endpoints.view',
+                'permission': 'endpoints.fleet',
                 'empty': 'hide',
                 'position': 22,
                 'map': {
@@ -358,7 +374,7 @@ class EndpointsPlugin(BasePlugin):
                 'endpoint': '/api/endpoints/dashboard/stability',
                 'render': 'exceptions',
                 'severity': 'critical',
-                'permission': 'endpoints.view',
+                'permission': 'endpoints.fleet',
                 'empty': 'hide',
                 'position': 16,
                 'map': {