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.

shopdb/__init__.py

@@ -81,7 +81,14 @@ from .plugins import plugin_manager
 # endpoints command claim/result long-poll callbacks) on the same per-plugin
 # collector key + managed-token check the ingest route uses, without importing
 # core collector internals. Additive name on the surface, minor bump.
-__contract_version__ = '0.24.0'
+# 0.25.0: added caller_holds(permission) to shopdb.api so a route can ask
+# whether THIS caller holds a permission without refusing the request. It is for
+# a surface that serves everyone but should only OFFER what the caller can use:
+# the endpoints services panel emitted Start/Stop to every reader because the
+# emission never consulted the caller, so a read-only viewer was shown controls
+# over a shop-floor PC that 403 on click. Guests are included, since a signed-out
+# visitor holds whatever the guest role was granted. Additive name, minor bump.
+__contract_version__ = '0.25.0'
 
 # Product release version (see ADR-007). The product version and the
 # plugin-contract version above are distinct series with independent