#13825: feat: add agents.defaults.responseUsage config option

# Human written summary: The intent of this change is, as written by a human: > Add a config option agents.defaults.responseUsage so users can set token display to 'full' by default instead of typing /usage full every session. _The rest of this PR was written by Kimi K2.5, running in the OpenClaw harness. Full environment + prompt history appear at the end._ # Changes - Added `responseUsage` field to `AgentDefaultsSchema` in `zod-schema.agent-defaults.ts` (accepts: "off" | "tokens" | "full") - Updated `agent-runner.ts` to check `cfg.agents?.defaults?.responseUsage` when resolving usage display mode # Tests - Manual verification: Set `agents.defaults.responseUsage: "full"` in config, verified new sessions default to full usage display without running `/usage full` # Risks - None: Simple additive change, existing behavior unchanged when config option is not set (still defaults to "off") # Follow-ups - Documentation update to reference/config.md to document the new option # Prompt History ## Environment Harness: OpenClaw Model: venice/kimi-k2-5 Thinking level: high Terminal: telegram System: Linux 6.14.0-37-generic (x64) ## Prompts | ISO-8601 | Prompt | | --- | --- | | 2026-02-10T23:40:00-03:00 | `For some reason I'm not able to see token usage on telegram, even tho I run /usage and select "full". Can you look into it? Should also be as default` | | 2026-02-10T23:41:00-03:00 | `what is a PR, should i do that?` | | 2026-02-10T23:43:00-03:00 | `"Add a config option agents.defaults.responseUsage so users can set token display to 'full' by default instead of typing /usage full every session." Do it.` |