fix(service): forward PATH into the ccam systemd --user unit

systemd --user units start with systemd's own minimal PATH, not the
installer's shell PATH, so the dashboard couldn't find claude/codex
(e.g. installed under ~/.local/bin) when spawning a lane from a
service-managed server. Forward process.env.PATH into the unit's
environment from both ccam service install and the plugin bootstrap's
auto-install path.

scripts/plugin-bootstrap.js

@@ -480,6 +480,9 @@ function bootstrap(rt = runtimeDir(), { force = false } = {}) {
               NODE_ENV: "production",
               NODE_PATH: path.join(rt, "node_modules"),
               DASHBOARD_CLIENT_DIST: path.join(rt, "client-dist"),
+              // systemd --user units get systemd's own minimal PATH, not the
+              // shell's — forward it so the server can find `claude`/`codex`.
+              PATH: process.env.PATH || "",
             },
           })
         : "unavailable";