refactor(gateway): cyclic-subscription samplers and the bulk-data store come from the core

docs/api/rest.rst

@@ -2158,7 +2158,11 @@ collection.
    - ``resource`` (string, required): Full SOVD resource URI to observe
      (e.g. ``/api/v1/apps/{id}/data/{topic}``, ``/api/v1/apps/{id}/faults``,
      ``/api/v1/functions/{id}/x-medkit-graph``). The URI ends at the collection
-     unless that collection's sampler narrows its payload to a named resource
+     unless that collection's sampler narrows its payload to a named resource.
+     The item path is percent-decoded as a GET path is, so an encoded topic or
+     plugin item name addresses the item GET of the same URI reads. A
+     member-qualified id (``member:/topic``) is not resolved by a subscription;
+     use the bare item id.
    - ``protocol`` (string, optional): Transport protocol. Only ``"sse"`` supported. Default: ``"sse"``
    - ``interval`` (string, required): One of ``fast``, ``normal``, ``slow``
    - ``duration`` (integer, required): Subscription lifetime in seconds.

docs/config/server.rst

@@ -696,7 +696,7 @@ Bulk Data Storage
 -----------------
 
 Configure file-based bulk data storage for uploads (calibration files, firmware, etc.).
-The ``rosbags`` category is always available via the Fault Manager and does not need
+The ``rosbags`` category is served by the Fault Manager and does not need
 configuration.
 
 .. list-table::
@@ -733,8 +733,9 @@ Example:
 
 .. note::
 
-   The ``rosbags`` category is always available through the Fault Manager and cannot be
-   used for uploads or deletes. It is automatically included in the category list.
+   The ``rosbags`` category is available through the Fault Manager and cannot be
+   used for uploads or deletes. It is included in the category list whenever the Fault
+   Manager serves rosbags, which is always the case on the ROS 2 node.
 
 .. note::
 

scripts/check_cores_without_ros/README.md

@@ -17,6 +17,13 @@ not installed, so the PostgreSQL backend is not built.
 
 ## What `main.cpp` checks
 
+- Cyclic subscriptions: with `register_builtin_samplers()` and the SSE transport, a subscription on a data resource (served by
+  a controlled `TopicDataProvider`), on a resource a plugin's `DataProvider` serves, and on faults each stream two events whose
+  values differ.
+- Bulk data: a store built by `make_bulk_data_store()` takes an upload over HTTP, lists it, returns it byte-equal and deletes
+  it; an upload past `max_upload_size` is refused; the categories do not contain `rosbags` when the fault manager serves none.
+- `GET /` capabilities: `bulk_data` and `cyclic_subscriptions` are false for services without a store, rosbags, transport or
+  sampler, and true as soon as a store or rosbags (bulk data), or a transport and a sampler (subscriptions), exist.
 - Gateway: with `server_name`, `vendor_name` and `server_version` set in `RestConfig`, `GET /api/v1/` returns the name and version, and `GET /api/v1/version-info` returns the vendor name and version.
 
 - Reporter core: a report below the local filter threshold is filtered, the next one reaches the sink, a PASSED report is