fix(config): prevent custom endpoint slug collisions from cross-routing API credentials

[Drexuxux]

What?

Distinct custom endpoint IDs such as acme-prod and acme_prod were mapped to the same .env variable.

Saving the second endpoint overwrote the first credential, causing runtime resolution to pair Endpoint A's URL with Endpoint B's API key.

Fix

Custom endpoint credential slots now include a stable SHA-256 digest, preserving identity differences that the readable slug removes.

Legacy slots remain supported during rotation, clearing, and deletion. Active model mirrors are migrated before old credentials are removed, and shared legacy slots are retained until their final reference is gone.

Related work

• fix(cli): store custom endpoint API key in .env instead of config.yaml #57557 introduced .env storage for custom endpoint credentials.
• fix: custom endpoint keys go to .env, and Save keeps the whole model list #71141 merged the unified Desktop/CLI credential flow and identity-based slot naming.
• [Security] Custom endpoint API key stored in plaintext in config.yaml #69449 reported plaintext custom endpoint credentials.

These changes moved secrets out of config.yaml, but did not prevent punctuation-normalization collisions between distinct endpoint identities.

No matching open or closed issue/PR was found. #45481 concerns provider entries overwriting by shared base URL and is a different code path.

Tests

• Current main reproduction: Endpoint A resolved with Endpoint B's API key.
• Fixed branch: both endpoints retain and resolve only their own credentials.
• Targeted regression coverage: 10 passed.
• Broader suites: 494 passed / 24 skipped and 376 passed / 1 skipped.
• Four excluded failures were reproduced unchanged on clean upstream/main.
• Ruff, compileall, and git diff checks passed.

[teknium1]

Thanks for isolating this credential-routing bug. The current implementation still has the reported collision: hermes_cli/config.py:3953-3954 normalizes both acme-prod and acme_prod to the same slot; hermes_cli/web_server.py:7192-7197 writes that slot into each endpoint; and hermes_cli/runtime_provider.py:1115-1127 resolves the configured slot at runtime.

The digest-based slot in 98fb32788833 preserves the readable identity while separating punctuation-distinct IDs. Its legacy-reference guard also avoids removing a shared pre-digest slot while another configured endpoint still names it.

This is an automated hermes-sweeper review.