fix: /approve and /deny outside REPL emit interactive_only error_kind (#828)

/approve, /yes, /deny, /no (and /y, /n) are valid REPL-only slash
commands. Outside the REPL they were falling through to
format_unknown_direct_slash_command -> error_kind:unknown_slash_command.

Fix: intercept them in the SlashCommand::Unknown arm and emit
interactive_only: prefix so classify_error_kind returns the correct kind.

One new test: approve_deny_outside_repl_emits_interactive_only (covers
/approve, /yes, /deny, /no)

572 tests pass, 1 pre-existing worker_boot failure unrelated.

rust/crates/rusty-claude-cli/src/main.rs

@@ -1739,7 +1739,20 @@ fn parse_direct_slash_cli_action(
                 }),
             }
         }
-        Ok(Some(SlashCommand::Unknown(name))) => Err(format_unknown_direct_slash_command(&name)),
+        Ok(Some(SlashCommand::Unknown(name))) => {
+            // #828: /approve and /deny are valid REPL-only slash commands that
+            // are not SlashCommand enum variants (they require an active tool
+            // call in the REPL to be meaningful). Emit interactive_only so
+            // machine consumers see the correct error_kind instead of
+            // unknown_slash_command.
+            if matches!(name.as_str(), "approve" | "yes" | "y" | "deny" | "no" | "n") {
+                Err(format!(
+                    "interactive_only: /{name} requires an active tool call in the REPL.\nStart `claw` and use /{name} to approve or deny a pending tool execution."
+                ))
+            } else {
+                Err(format_unknown_direct_slash_command(&name))
+            }
+        }
         Ok(Some(command)) => Err({
             let _ = command;
             format!(