fix: #127 reject unrecognized suffix args for diagnostic verbs

Diagnostic verbs (help, version, status, sandbox, doctor, state) now
reject unrecognized suffix arguments at parse time instead of silently
falling through to Prompt dispatch.

Fixes: claw doctor --json (and similar) no longer accepts --json silently
and attempts to send it to the LLM as a prompt. Now properly emits:
'unrecognized argument `--json` for subcommand `doctor`'

Joined parser-level trust gap quintet #108 + #117 + #119 + #122 + #127.
Prevents token burn on rejected arguments.

Verified: cargo build --workspace passes, claw doctor --json errors cleanly.

Refs: #127, ROADMAP

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

@@ -746,6 +746,31 @@ fn parse_single_word_command_alias(
     permission_mode_override: Option<PermissionMode>,
     output_format: CliOutputFormat,
 ) -> Option<Result<CliAction, String>> {
+    if rest.is_empty() {
+        return None;
+    }
+
+    // Diagnostic verbs (help, version, status, sandbox, doctor, state) accept only the verb itself
+    // or --help / -h as a suffix. Any other suffix args are unrecognized.
+    let verb = &rest[0];
+    let is_diagnostic = matches!(
+        verb.as_str(),
+        "help" | "version" | "status" | "sandbox" | "doctor" | "state"
+    );
+
+    if is_diagnostic && rest.len() > 1 {
+        // Diagnostic verb with trailing args: reject unrecognized suffix
+        if is_help_flag(&rest[1]) && rest.len() == 2 {
+            // "doctor --help" is valid, routed to parse_local_help_action() instead
+            return None;
+        }
+        // Unrecognized suffix like "--json"
+        return Some(Err(format!(
+            "unrecognized argument `{}` for subcommand `{}`",
+            rest[1], verb
+        )));
+    }
+
     if rest.len() != 1 {
         return None;
     }