Function setGlobalRate

setGlobalRate(
    config: FirewallConfig,
    napplet: string,
    limit: RateLimit,
): FirewallConfig
Set a per-napplet global fallback rate limit (RATE-03).

The global rate is applied to all op-classes for this napplet that lack a specific rateLimits entry. This provides a single budget covering all unlisted operations rather than relying solely on the config-wide defaultRate.

Returns a new FirewallConfig with napplets[napplet].globalRate set. The original config is never modified.
Parameters
- config: FirewallConfig
  Current firewall config
- napplet: string
  Napplet dTag to configure
- limit: RateLimit
  Global fallback rate limit for this napplet
Returns FirewallConfig
New FirewallConfig with the global rate set
Example
```
const cfg2 = setGlobalRate(cfg, 'chat', { capacity: 30, windowMs: 30000, action: 'flag' });
// cfg2.napplets['chat'].globalRate is set; other napplets unaffected
```
- Defined in config.ts:125