feat: unified gateway route table (static · proxy · remote)

The gateway does two things — reverse-proxy services and serve static
frontends — but the dashboard/API route table only ever showed the proxy
routes, so 'serving a frontend' and 'proxying a service' looked like unrelated
features and castle-app/power-graph-app were invisible in the route view.

Now there's one concept: a route maps an address (path '/foo' or host 'foo.lan')
to a target of one kind — static (a built dist served by file_server), proxy
(a local service port), or remote (a service on another node).

- core: caddyfile.py gains compute_routes() — the single source of truth for
  the route list; generate_caddyfile_from_registry renders it (output byte-for-
  byte identical, verified against the live Caddyfile). Adds a GatewayRoute
  dataclass.
- api: GatewayRoute model → {address, kind, target, name, node}; GET /gateway
  builds from compute_routes (incl. config for static frontends + mesh for
  remote), so the table matches what Caddy actually does.
- app: Gateway panel shows Address · Kind · Target for every route (static
  frontends + host routes now appear); program detail shows 'Reachable at
  /foo/ · served (static)' for static frontends.
- cli: 'castle gateway status' prints the full route table.
- docs: registry.md/design.md/CLAUDE.md describe routes as one concept with
  three target kinds.

core 94 / cli 24 / api 52 green; ruff + app build clean; Caddyfile unchanged.

cli/src/castle_cli/commands/gateway.py

@@ -116,17 +116,30 @@ def _gateway_reload() -> int:
 
 
 def _gateway_status() -> int:
-    """Show gateway status via systemd."""
+    """Show gateway status + the full route table (static, proxy, remote)."""
     result = subprocess.run(
         ["systemctl", "--user", "is-active", GATEWAY_UNIT],
         capture_output=True,
         text=True,
     )
     status = result.stdout.strip()
+    print(f"Gateway: {'running' if status == 'active' else status}")
 
-    if status == "active":
-        print("Gateway: running")
-    else:
-        print(f"Gateway: {status}")
+    if not REGISTRY_PATH.exists():
+        print("  (no registry — run 'castle deploy')")
+        return 0
 
+    from castle_core.generators.caddyfile import compute_routes
+
+    routes = compute_routes(load_registry())
+    if not routes:
+        print("  No routes configured.")
+        return 0
+
+    # Each route: address → target, tagged by kind. static = files served in
+    # place; proxy/remote = reverse-proxied to a process.
+    print(f"\n  {'ADDRESS':24} {'KIND':7} TARGET")
+    for r in routes:
+        target = r.target.replace("localhost:", ":") if r.kind != "static" else r.target
+        print(f"  {r.address:24} {r.kind:7} {target}")
     return 0