Parse auth cookies without requiring spaces

[aiirvizionz]

Fixes an auth edge case in the crypto public-key routes.

The public-key endpoints parsed Cookie headers with split("; "), which only works when every semicolon is followed by a space. Valid Cookie headers may be serialized as a=1;b=2 by clients/proxies. In that case the Supabase auth cookie and session cookie could be merged into one parsed value, causing authenticated key fetch/sync requests to fail as unauthorized.

This PR changes those parsers to split on ; with optional whitespace and adds a regression test for a Supabase base64-... auth cookie followed immediately by another cookie without a space.

Validation:

• npx vitest run src/app/api/crypto/public-keys/route.test.js
• node --check src/app/api/crypto/public-keys/route.js
• node --check src/app/api/crypto/public-keys/all/route.js
• node --check src/app/api/crypto/public-keys/route.test.js
• git diff --check