refactor(maestro): drop allow_inbound policy gate, keep JWT session binding (NAP-339)

The peer (T2) attach path had a per-pair access-control layer
(`[daemon.policy].allow_inbound`): a target-side allow-list of daemon ids
permitted to broker-attach, enforced inside JWT verification, hot-reloadable via
SIGHUP / `POST /api/policy/reload`, with a `maestro policy` CLI. On a flat-trust
perimeter (the operator's VPN/firewall is the boundary for which hosts connect)
that granularity is unused, and deny-by-default made it config friction —
cross-daemon attach silently failed until every peer was listed.

Remove the allow-list; keep the registry-minted pair-attach JWT and ALL its
binding checks (iss=registry, aud=target, sid=session, exp). The firewall gates
host->port reachability; it does not stop a reachable host from attaching to a
session it wasn't handed or replaying a token elsewhere — that's the JWT's job
and it stays. Only the `sub in allow_inbound` check is dropped.

Removed: DaemonPolicySection / [daemon.policy].allow_inbound (config + daemon),
policy.rs (SIGHUP listener + GET/POST /api/policy), the `maestro policy` CLI,
PairAttachVerifier's allow-list field/reload/snapshot + JwtError::NotAllowed,
and the e2e broker_rejects_when_target_doesnt_allow_inbound test. The NAP-265
pre-upgrade-502 path stays covered by broker_attach_returns_502_on_perimeter_mismatch.

Also dropped the unit's ExecReload=kill -HUP: with no SIGHUP handler left,
default SIGHUP disposition is terminate, so wiring `systemctl reload` to it would
kill the daemon. Re-introducing a per-pair gate later is a verify-time change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/maestro-e2e/src/daemon.rs

@@ -27,13 +27,12 @@ pub struct Daemon {
     token: String,
 }
 
-/// Optional knobs for `Daemon::spawn_with` — perimeter + allow_inbound for
+/// Optional knobs for `Daemon::spawn_with` — perimeter advertisement for
 /// NAP-247 broker tests.
 #[derive(Debug, Default, Clone)]
 pub struct DaemonOptions {
     pub perimeter_id: Option<String>,
     pub private_addr: Option<String>,
-    pub allow_inbound: Vec<String>,
 }
 
 impl Daemon {
@@ -50,7 +49,7 @@ impl Daemon {
         .await
     }
 
-    /// Spawn with NAP-247 options (perimeter advertisement, allow_inbound).
+    /// Spawn with NAP-247 options (perimeter advertisement).
     pub async fn spawn_with(
         daemon_id: &str,
         registry_base_url: &str,
@@ -116,11 +115,6 @@ impl Daemon {
         let state = TempDir::new().expect("state tmpdir");
         let tmux = TempDir::new().expect("tmux tmpdir");
 
-        // Write a minimal config.toml so allow_inbound (and any future
-        // file-only fields) reach the daemon. Required fields keep coming
-        // through env vars set by `launch`.
-        write_config(home.path(), &opts);
-
         let daemon_url = format!("ws://{bind}");
         let child = launch(
             daemon_id,
@@ -219,25 +213,3 @@ fn launch(
     cmd.spawn()
         .unwrap_or_else(|e| panic!("spawn {} failed: {e}", bin.display()))
 }
-
-/// Write a minimal `~/.config/maestro/config.toml` carrying the NAP-247
-/// `[daemon.policy] allow_inbound` list. Everything else still comes from
-/// env vars set by `launch`.
-fn write_config(home: &std::path::Path, opts: &DaemonOptions) {
-    if opts.allow_inbound.is_empty() {
-        return;
-    }
-    let dir = home.join(".config/maestro");
-    std::fs::create_dir_all(&dir).unwrap();
-    let mut allow = String::new();
-    for (i, id) in opts.allow_inbound.iter().enumerate() {
-        if i > 0 {
-            allow.push_str(", ");
-        }
-        allow.push('"');
-        allow.push_str(id);
-        allow.push('"');
-    }
-    let body = format!("[daemon.policy]\nallow_inbound = [{allow}]\n");
-    std::fs::write(dir.join("config.toml"), body).unwrap();
-}