feat-add: anchor cli keygen

[dotslashapaar]

Implement anchor keygen commands (new/pubkey/recover) to reduce Solana CLI dependency (#3866 )

• Adds native keypair generation, public key extraction, and seed phrase recovery functionality to Anchor CLI, eliminating the need to shell out to solana-keygen.
• Commands work both inside and outside workspace directories, providing flexibility for developers.

Dependencies added:

• tiny-bip39 = "2.0"
• ed25519-dalek-bip32 = "0.3"

[vercel]

@dotslashapaar is attempting to deploy a commit to the Solana Foundation Team on Vercel.

A member of the Team first needs to authorize it.

[jamie-osec]

Closing in favour of #3963