fix: report a clear cli error when no herdr server is running (#1963)

* fix: report a clear cli error when no herdr server is running

socket cli commands surfaced a raw io::Error debug string
(`Error: Os { code: 2, ... }`) when nothing was listening on the
api socket, which read like a bad --cwd path. map dead-socket
connect failures to a `server_not_running` json error carrying the
resolved socket path, printed once at the edge that surfaces the
error; recovering callers (plugin offline registry fallback, agent
start polling) recognize the marker and keep their existing
behavior.

refs #1941

* fix: map dead-socket errors on the unchecked cli request path

refs #1941

* fix: make server-not-running guidance session-aware

refs #1941

1 files changed, 8 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index 8fc51d6b..7b4058d2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -497,6 +497,14 @@ fn main() -> io::Result<()> {
         Ok(cli::CommandOutcome::Handled(code)) => std::process::exit(code),
         Ok(cli::CommandOutcome::NotCli) => {}
         Err(err) if cli::protocol_mismatch_was_reported(&err) => std::process::exit(1),
+        Err(err) if cli::server_not_running_was_reported(&err) => {
+            if let Some(response) = cli::server_not_running_reported_response(&err) {
+                if let Ok(json) = serde_json::to_string(response) {
+                    eprintln!("{json}");
+                }
+            }
+            std::process::exit(1);
+        }
         Err(err) => return Err(err),
     }