Change network protocol selections at runtime

Protocol selection previously belonged to tsng up and therefore to the
service command line. A blocked or degraded carrier could only be removed
by editing the service and restarting the whole agent. Make the ordered
selection a local per-network setting instead.

Add Agent::set_protocols and a local control request shared by CLI and tray.
Keep tsng protocols without arguments as the protocol catalog; naming a
network shows its selection and supplying a comma-separated list replaces
it. Accept exact names, full ids and unique prefixes using shared selector
rules; ambiguous selectors and invalid lists change nothing. An explicit
none selects control-only operation. Offline edits take the directory lock
and apply on the next start; live edits never write behind the daemon.

Register every built-in plugin and transport in the CLI. Treat up --protocol
as ordered initial defaults for networks without an override, allowing a
protocol absent from the unit to be enabled later. Retain the targeting of
unqualified startup options and allow explicitly scoped options to configure
initially disabled protocols. Persist NULL for inherited preferences and an
empty selection distinctly in SQLite schema 8; migration preserves existing
identities, secrets, signed records and counters.

Serialize changes with network lifecycle operations and commit preferences
before applying or announcing them. Retire only the affected network's data
links and E2E channels, cancel pending opens, and reject obsolete completion
results by attempt id. Clear peer data channels when authenticated protocol
capabilities change while retaining control sessions and topology. Replay
allocations and peer identities after asynchronously prepared plugins become
ready. A control-only start defers creation of the agent's single interface
until data is enabled; plugins receive a sink that can use it later. Automatic
carrier fallback continues to preserve E2E state; explicit policy changes
renegotiate it. Identity derivation and peer wire formats are unchanged.

Add a collapsible protocols row to each tray network tile, with a catalog
provided by the daemon, descriptions, immediately applied checkboxes and
preference-order buttons. Keep editing disabled until the worker refreshes
status so a second click cannot overwrite an edit using a stale snapshot.
Local IPC wire version is 20 for the new request and report fields; upgrade
and restart agent, CLI and tray together. Crate release versions remain unchanged; the requested RC tag is v0.1.0-rc.30.

Validation on Linux through nix develop:
- cargo fmt --all -- --check
- cargo clippy --locked --workspace --all-targets -- -D warnings
- cargo test --locked --workspace --all-targets: 509 passed, 2 existing ignored
  tests, with inherited TSUNAGI_CONTROL_SOCKET and TSUNAGI_CONTROL_GROUP removed

Tests use real iroh membership, SQLite, UDP, AWG and WireGuard encryption,
QUIC carriers and memory TUNs. Cover either endpoint-id role, full-size packet
delivery after switching, an unaffected second active network, saved selection
after restart, empty/invalid selections, first enablement without restart,
rapid changes racing old opens, live and offline CLI changes, startup-absent
protocols and preservation of signed state through migration. Earlier compile
and focused-test iterations caught initializer mistakes, a short test secret,
asynchronous plugin allocation readiness, and an inherited system socket
path; corrected before the successful final checks. Plain cargo was unavailable
in the host shell, so validation used the Nix toolchain. Manual tray interaction,
macOS/Windows, privileged host TUNs and public-network traversal were not run.

crates/tsunagi-core/src/ipc/mod.rs

@@ -171,6 +171,13 @@ pub fn default_control_socket_path() -> PathBuf {
 #[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[non_exhaustive]
 pub enum Request {
+    /// Replace one network's ordered local data-plane selection.
+    SetProtocols {
+        /// Public network identifier.
+        network_id: String,
+        /// Protocol names, best first; empty selects control only.
+        protocols: Vec<String>,
+    },
     /// Report what the agent is doing.
     Status,
     /// Set local broadcast participation in one configured network.
@@ -255,6 +262,13 @@ pub enum Request {
 impl std::fmt::Debug for Request {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
+            Request::SetProtocols {
+                network_id,
+                protocols,
+            } => write!(
+                f,
+                "SetProtocols {{ {network_id}, protocols: {protocols:?} }}"
+            ),
             Request::Status => f.write_str("Status"),
             Request::SetBroadcast {
                 network_id,
@@ -286,6 +300,8 @@ impl std::fmt::Debug for Request {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[non_exhaustive]
 pub enum Response {
+    /// Accepted ordered protocol selection.
+    Protocols(Vec<String>),
     /// A status report.
     Status(Box<StatusReport>),
     /// Accepted local broadcast participation.
@@ -377,6 +393,8 @@ pub struct LeftReport {
 /// Everything the agent is doing, in one snapshot.
 #[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct StatusReport {
+    /// Data-plane protocols this agent can enable at runtime.
+    pub available_protocols: Vec<ProtocolReport>,
     /// This device's persistent endpoint id.
     pub endpoint_id: String,
     /// Hostname announced to peers.
@@ -458,9 +476,20 @@ pub struct RangeConflictReport {
     pub range: String,
 }
 
+/// A data-plane protocol available in the running agent.
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ProtocolReport {
+    /// Stable protocol name used by the CLI and network negotiation.
+    pub name: String,
+    /// A short description of encryption and transport.
+    pub summary: String,
+}
+
 /// One network.
 #[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct NetworkReport {
+    /// Enabled local data-plane protocols, in preference order.
+    pub protocols: Vec<String>,
     /// Whether the network starts or resumes automatically when its range is free.
     #[serde(default)]
     pub auto_start: bool,
@@ -720,6 +749,14 @@ impl OverlayPeerReport {
 /// running and what they can report or change. That is what keeps this module
 /// free of any knowledge of them.
 pub trait ReportSource: Send + Sync + 'static {
+    /// Saves and applies a local ordered protocol set for one network.
+    fn set_protocols(
+        &self,
+        _network_id: String,
+        _protocols: Vec<String>,
+    ) -> BoxFuture<'_, std::result::Result<Vec<String>, String>> {
+        Box::pin(async { Err("this agent cannot change protocols".into()) })
+    }
     /// Produces a fresh report.
     fn report(&self) -> BoxFuture<'_, StatusReport>;
 
@@ -849,7 +886,7 @@ pub const EXCHANGE_TIMEOUT: Duration = Duration::from_secs(5);
 ///
 /// Bump it whenever [`Request`], [`Response`] or anything they contain
 /// changes shape.
-pub const CONTROL_PROTOCOL: u32 = u32::from_be_bytes([b'T', b'S', b'N', 19]);
+pub const CONTROL_PROTOCOL: u32 = u32::from_be_bytes([b'T', b'S', b'N', 20]);
 
 /// Reads one request off an accepted stream, answers it, writes the response.
 ///
@@ -873,6 +910,13 @@ where
             }
         };
     let response = match request {
+        Request::SetProtocols {
+            network_id,
+            protocols,
+        } => match source.set_protocols(network_id, protocols).await {
+            Ok(protocols) => Response::Protocols(protocols),
+            Err(reason) => Response::Error(reason),
+        },
         Request::Status => Response::Status(Box::new(source.report().await)),
         Request::SetBroadcast {
             network_id,
@@ -1028,7 +1072,24 @@ pub async fn join_network_with_broadcast(
     }
 }
 
-/// Changes one network's broadcast participation while the agent runs.
+/// Replaces the enabled data-plane protocols of one configured network.
+pub async fn set_protocols(
+    socket: &Path,
+    network_id: &str,
+    protocols: Vec<String>,
+) -> Result<Vec<String>> {
+    let request = Request::SetProtocols {
+        network_id: network_id.to_owned(),
+        protocols,
+    };
+    match exchange(socket, &request, EXCHANGE_TIMEOUT).await? {
+        Response::Protocols(protocols) => Ok(protocols),
+        Response::Error(reason) => Err(Error::Storage(reason)),
+        other => Err(Error::Storage(format!("unexpected response: {other:?}"))),
+    }
+}
+
+/// Changes local broadcast participation in a network.
 pub async fn set_broadcast(
     path: impl AsRef<Path>,
     network_id: &str,