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-cli/src/dispatch.rs

@@ -11,7 +11,8 @@
 //! * `list` reads the daemon's local catalog mirror (own ∪ peer sessions).
 //! * `spawn` / `kill` hit the daemon's local session endpoints.
 //! * `attach` opens the daemon's `WS /api/attach/:id` broker, which picks the
-//!   transport and enforces `allow_inbound` on the target side.
+//!   transport and dials the target (the target verifies the registry-minted
+//!   pair-attach JWT — session binding, not a per-peer allow-list).
 //!
 //! If the home daemon is **unreachable** (connection refused / not running),
 //! every command falls back to the legacy registry path (registry HTTP +
@@ -23,10 +24,9 @@
 use std::path::{Path, PathBuf};
 
 use crate::attach::{broker_attach_url, parse_detach_key, run_attach, run_attach_url};
-use crate::cli::{AttachArgs, Command, KillArgs, ListArgs, PolicyCmd, SetRegistryArgs, SpawnArgs};
+use crate::cli::{AttachArgs, Command, KillArgs, ListArgs, SetRegistryArgs, SpawnArgs};
 use crate::config::{default_config_path, CliConfig, ConfigError};
 use crate::http::{HttpError, RegistryClient};
-use crate::policy::{run_reload as run_policy_reload, run_show as run_policy_show};
 use crate::sessions::{fetch_connect_info, run_kill, run_list, run_spawn};
 
 #[derive(Debug, thiserror::Error)]
@@ -40,8 +40,6 @@ pub enum CliError {
     Attach(#[from] crate::attach::AttachError),
     #[error("{0}")]
     Io(#[from] std::io::Error),
-    #[error("{0}")]
-    Policy(#[from] crate::policy::PolicyError),
 }
 
 /// Dispatch a parsed top-level subcommand. The umbrella binary passes the
@@ -61,7 +59,6 @@ pub async fn dispatch(
 
     match command {
         Command::SetRegistry(args) => set_registry(&config_path, args),
-        Command::Policy(sub) => policy(&config_path, sub).await,
         Command::List(args) => {
             list(
                 &config_path,
@@ -109,16 +106,6 @@ fn set_registry(config_path: &Path, args: SetRegistryArgs) -> Result<(), CliErro
     Ok(())
 }
 
-#[allow(clippy::result_large_err)]
-async fn policy(config_path: &Path, sub: PolicyCmd) -> Result<(), CliError> {
-    let mut stdout = std::io::stdout().lock();
-    match sub {
-        PolicyCmd::Reload => run_policy_reload(config_path, &mut stdout).await?,
-        PolicyCmd::Show { json } => run_policy_show(config_path, json, &mut stdout).await?,
-    }
-    Ok(())
-}
-
 #[allow(clippy::result_large_err)]
 async fn list(
     config_path: &Path,