feat(search): add ANONYMOUS_SEARCH to skip the login for a service

A service that sets the flag gets no cookie load, no authenticate() call and no cookie save on a search, on the CLI and in the REST search handler. /api/services reports it as anonymous_search.

docs/dev/rest-api/endpoints.md

@@ -98,6 +98,7 @@ Show the streaming services available on this server, filtered by your allowlist
           ],
           "needs_auth": true,
           "has_search": true,
+          "anonymous_search": false,
           "has_drm": true,
           "auth_methods": ["cookies"]
         }
@@ -120,6 +121,7 @@ Field notes:
 | `cli_params` | Array of parameter descriptors. Arguments have `{name, kind: "argument", required}`; options have `{name, kind: "option", opts, is_flag, default, help, type, multiple}` and, for choice options, a `choices` list. |
 | `needs_auth` | Whether the service overrides `authenticate()`. |
 | `has_search` | Whether the service supports `POST /api/search`. |
+| `anonymous_search` | Whether `POST /api/search` operates with no login for this service. The server then ignores `credentials` and `cookies` on a search. |
 | `has_drm` | Whether the service overrides a Widevine or PlayReady license hook. |
 | `pending_update` | Set to `true` while a service repository refresh waits for this service's jobs to finish before it swaps in the new code. Absent otherwise. |
 | `server_accounts` | Present when the server lends its own accounts for this service: `{regions: ["ca", "gb"], global: bool}`, the regions those accounts cover. A client sends no credentials, cookies, or cache for such a service. |
@@ -134,6 +136,8 @@ Field notes:
 
 Find titles in a service by query string. The service must have a `search()` method (see `has_search` above).
 
+For a service with `anonymous_search`, the server does not log in and ignores `credentials` and `cookies`. The server account check still applies.
+
 **Request body**
 
 | Field | Type | Required | Default | Description |

docs/dev/rest-api/quickstart.md

@@ -150,6 +150,7 @@ curl "$BASE/api/services" \
       "help": "EXAMPLE service documentation...",
       "needs_auth": true,
       "has_search": true,
+      "anonymous_search": false,
       "has_drm": true,
       "auth_methods": ["cookies", "credentials"],
       "cli_params": []