node: Introduce Announcers — heartwood

Further decoupling user and node, as a follow up to

patch/05db4d7284c69875986a30b8161238b607155f5e

make the list of “announcers”, i.e. the namespaces that are commonly announced from the node, and for which sync status should be tracked, configurable.

     G: crypto::signature::Signer<crypto::Signature>,
 {
     pub fn new(
         config: Config,
         mut config: Config,
         db: Stores<D>,
         storage: S,
         policies: policy::Config<Write>,

                 .with_max_capacity(fetcher::MaxQueueSize::default());
             FetcherService::new(config)
         };
         // For backwards compatibility, ensure that we are announcer of our own Node ID.
         config.announcers.insert(*signer.public_key());
         Self {
             config,
             storage,

                 // from a new repository being initialized.
                 self.seed_discovered(message.rid, *announcer, message.timestamp);
                 // Update sync status of announcer for this repo.
                 if let Some(refs) = refs.iter().find(|r| &r.remote == self.nid()) {
                 // Update sync status of announcers for this repo.
                 for refs in refs
                     .iter()
                     .filter(|r| self.config.announcers.contains(&r.remote))
                 {
                     debug!(
                         target: "service",
                         "Refs announcement of {announcer} for {} contains our own remote at {} (t={})",
                         message.rid, refs.at, message.timestamp
                         "Refs announcement of {announcer} for {} contains announcer {} (t={})",
                         message.rid, refs, message.timestamp
                     );
                     match self.db.seeds_mut().synced(
                         &message.rid,

             #[derive(JsonSchema)]
             #[schemars(untagged)]
             #[allow(dead_code)]
             #[allow(dead_code, clippy::large_enum_variant)]
             enum CommandResult {
                 Nid(radicle::node::NodeId),
                 Config(Box<radicle::node::Config>),

     /// the environment variable `RAD_PASSPHRASE`.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub secret: Option<std::path::PathBuf>,
     #[serde(default, skip_serializing_if = "HashSet::is_empty")]
     pub announcers: HashSet<super::NodeId>,
 }
 impl Config {

             database: node::db::config::Config::default(),
             extra: json::Map::default(),
             secret: None,
             announcers: HashSet::new(),
         }
     }