Add opt-in BLE WiFi provisioning path

[tnm]

Adds BLE provisioning.

However, does exceed our build size limits. Is off by default for now; will explore adding it as a default if we reduce some other stuff.

[sayasyedakmal]

By the way, great job. I think this the smallest OpenClaw alternative

[tnm]

No longer exceeds our size limits, so will test and see how the UX is.

Size: 893456 bytes (872.52 KiB)
Limit: 909312 bytes (888.00 KiB)
PASS: binary is within 888 KiB budget.