fix(crypto): validate public key upserts

[aiirvizionz]

Summary

• reject non-string or blank public_key payloads before public-key upsert RPC work
• reject malformed key_type overrides and trim valid key values before storage
• add regression coverage for object public_key payloads

Test

• node node_modules\vitest\vitest.mjs run --config %TEMP%\qryptchat-vitest-minimal.config.mjs "src/app/api/crypto/public-keys/route.test.js"
• git diff --check

uGig billing

• Expected invoice: 0.50 USD if accepted/merged
• Counted as revenue now: no, pending review/payment