fix(docs): correct autospawn args default comment

COLIBRI_AUTOSPAWN_ARGS default is binary-dependent, not always
--mode json. zot uses 'rpc' (RPC mode), other harnesses use
--mode json. The code was correct (default_agent_args), the
doc comment was stale since the zot-rpc driver landed.

crates/colibri-daemon/src/socket.rs

@@ -410,7 +410,7 @@ async fn cmd_list_sessions(state: &SharedState) -> ColibriResponse {
 /// The live "Operator Image" is single-agent, so the agent runs on the host (no
 /// jail). Binary and argv are env-tunable without a rebuild:
 ///   - `COLIBRI_AUTOSPAWN_BINARY` (default `zot`)
-///   - `COLIBRI_AUTOSPAWN_ARGS` (default `--mode json`)
+///   - `COLIBRI_AUTOSPAWN_ARGS` (binary-dependent default; zot → `rpc`, others → `--mode json`)
 pub async fn autospawn_agent_if_configured(state: &SharedState) {
     if !env_truthy("COLIBRI_AUTOSPAWN") {
         return;