TC-1371 fix: canonicalize PKH DID addresses

[skgbafa]

Context

TC-1371 surfaced a production no_delegation loop where delegation status and backend access checks could disagree. The public symptom was a user appearing signed in while API calls still returned No delegation found. One class of failure here is treating EVM addresses and PKH DIDs as raw strings: lowercase addresses, EIP-55 checksum addresses, and DID URLs with fragments can identify the same principal but fail equality checks.

Summary

• Add tinycloud-auth identity helpers for canonical EIP-155 PKH DIDs.
• Canonicalize PKH space/resource IDs and encryption network IDs.
• Compare delegation, invocation, revocation, and delegation-list DIDs by canonical principal.
• Keep unsupported DID methods exact, so only supported PKH/EIP-155 principals get address normalization.

Tests

• cargo fmt
• cargo test -p tinycloud-auth
• cargo test -p tinycloud-core

Internal reference: TC-1371.