fix(permissions): return guidance for multi-word forms instead of falling through to LLM (#2994)

claw permissions list / claw permissions allow <tool> / claw permissions deny <tool>
all fell through to the prompt/LLM path because parse_subcommand had no
arm for "permissions". The single-word bare form was already intercepted
by bare_slash_command_guidance, but any form with rest.len() > 1 bypassed
the single-word guard and landed in the _other => CliAction::Prompt branch.

Fix: add a "permissions" arm in parse_subcommand that returns a structured
guidance Err so all multi-word forms get the same exit:1 + JSON error as
the bare single-word form, without any LLM call or session creation.

Verified: all invocation forms (bare, list, read-only, workspace-write,
allow/deny <tool>) exit 1 with kind:unknown guidance JSON. Zero sessions.

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

@@ -930,6 +930,14 @@ fn parse_args(args: &[String]) -> Result<CliAction, String> {
             }
             Ok(CliAction::Diff { output_format })
         }
+        // `claw permissions <mode>` falls through to the LLM when called
+        // with a subcommand argument because parse_single_word_command_alias
+        // only intercepts the bare single-word form. Catch all multi-word
+        // forms here and return a structured guidance error so no network
+        // call or session is created.
+        "permissions" => Err(format!(
+            "`claw permissions` is a slash command. Start `claw` and run `/permissions` inside the REPL.\n  Usage  /permissions [read-only|workspace-write|danger-full-access]"
+        )),
         "skills" => {
             let args = join_optional_args(&rest[1..]);
             match classify_skills_slash_command(args.as_deref()) {