feat(photon): add telemetry toggle via hermes photon telemetry

plugins/platforms/photon/cli.py

@@ -7,6 +7,7 @@ Subcommands:
     setup              full first-time setup (device login + project + user + sidecar)
     status             show login + project + sidecar dep state
     install-sidecar    npm install inside plugins/platforms/photon/sidecar/
+    telemetry          show or toggle Spectrum SDK telemetry (on/off)
 
 The device-code login runs automatically as the first step of ``setup``;
 there is no standalone ``login`` verb (matching how every other Hermes
@@ -58,6 +59,15 @@ def register_cli(parser: argparse.ArgumentParser) -> None:
     subs.add_parser("status", help="Show login + project + sidecar dep state")
     subs.add_parser("install-sidecar", help="Run npm install inside the sidecar directory")
 
+    p_telemetry = subs.add_parser(
+        "telemetry",
+        help="Show or toggle Spectrum SDK telemetry (on/off)",
+    )
+    p_telemetry.add_argument(
+        "state", nargs="?", choices=("on", "off"),
+        help="Turn telemetry on or off (omit to show the current state)",
+    )
+
     parser.set_defaults(func=dispatch)
 
 
@@ -75,6 +85,8 @@ def dispatch(args: argparse.Namespace) -> int:
         return _cmd_status(args)
     if sub == "install-sidecar":
         return _cmd_install_sidecar(args)
+    if sub == "telemetry":
+        return _cmd_telemetry(args)
     print(f"unknown subcommand: {sub}", file=sys.stderr)
     return 2
 
@@ -303,6 +315,7 @@ def _cmd_status(_args: argparse.Namespace) -> int:
     sidecar_installed = (_SIDECAR_DIR / "node_modules").exists()
     print(f"  node binary         : {node_bin or '✗ missing (install Node 18+)'}")
     print(f"  sidecar deps        : {'✓ installed' if sidecar_installed else '✗ run `hermes photon install-sidecar`'}")
+    print(f"  telemetry           : {'on' if _telemetry_enabled() else 'off'} (`hermes photon telemetry on|off`)")
     return 0
 
 
@@ -323,6 +336,37 @@ def _cmd_install_sidecar(_args: argparse.Namespace) -> int:
     return _install_sidecar()
 
 
+def _telemetry_enabled() -> bool:
+    """Read PHOTON_TELEMETRY from the env / ~/.hermes/.env.
+
+    Mirrors the sidecar's truthy set (index.mjs) so the state shown here
+    always matches what the sidecar will actually do.
+    """
+    try:
+        from hermes_cli.config import get_env_value
+        raw = get_env_value("PHOTON_TELEMETRY")
+    except ImportError:
+        raw = os.getenv("PHOTON_TELEMETRY")
+    return (raw or "").strip().lower() in ("1", "true", "yes", "on")
+
+
+def _cmd_telemetry(args: argparse.Namespace) -> int:
+    state = getattr(args, "state", None)
+    if state is None:
+        print(f"Photon telemetry: {'on' if _telemetry_enabled() else 'off'}")
+        print("  Toggle with `hermes photon telemetry on` / `hermes photon telemetry off`.")
+        return 0
+    try:
+        from hermes_cli.config import save_env_value
+        save_env_value("PHOTON_TELEMETRY", "true" if state == "on" else "false")
+    except Exception as e:
+        print(f"could not save PHOTON_TELEMETRY: {e}", file=sys.stderr)
+        return 1
+    print(f"✓ Spectrum telemetry turned {state} (PHOTON_TELEMETRY in ~/.hermes/.env)")
+    print("  Restart the gateway for the sidecar to pick it up:  hermes gateway restart")
+    return 0
+
+
 def _install_sidecar() -> int:
     npm = shutil.which("npm") or "npm"
     if not shutil.which(npm):