fix: prevent duplicate Zap battery readings

[frahlg]

What changed

• Add a Disable battery readings control for multi-resource HTTP gateways such as Sourceful Zap.
• Show it only when the signed catalog says the driver reports both the site meter and a battery.
• Keep Zap battery reporting enabled by default for sites that use Zap as their only battery source.

Why

Zap already supports config.disable_battery, but Settings did not expose it. A site with both a native battery driver and Zap could therefore report the same physical battery twice. Combined then added both readings.

Test plan

• node --test web/setup.test.mjs
• npm test
• go test ./internal/drivers -run TestZapDisableFlagsAvoidDuplicateNativeDrivers -count=1
• make verify
• pre-push make verify-all