fix(dashboard): prevent SSO auto-redirect crash on password-only providers

[gigakun3030]

Prevent SSO auto-redirect flow from triggering on password-only authentication providers, which causes 500 errors. Filters out these providers in the SSO middleware check.

[alt-glitch]

This was generated by AI during triage.

Duplicate of #54887 — same code site (_auto_sso_response in hermes_cli/dashboard_auth/middleware.py) and same supports_password mechanism to skip auto-SSO for password-only providers. #54887 is the earliest-open canonical fix of this cluster (into which #57427/#58044/#60247/#58905 also dedup). This PR filters password-only providers before the length check rather than returning None after it — a minor variation of the same fix. Related anchor issue: #55130.

[teknium1]

Thanks for the focused dashboard-auth fix. This is an automated hermes-sweeper review; current main already provides the requested behavior, so this PR is superseded.

• hermes_cli/dashboard_auth/middleware.py:190 returns None when the sole provider has supports_password=True, falling back to /login rather than auto-starting OAuth.
• Commit 3e24b16f566045399012bc1185fe0cdb6e1a1be9 added that guard and is present in current main.
• hermes_cli/dashboard_auth/routes.py:195-202 also redirects direct /auth/login?provider=<password-provider> requests to /login, covering the reported 500 route.
• This matches the prior duplicate triage on fix(dashboard-auth): skip auto-SSO redirect for password-only providers #54887, whose discussion records the same guard and its superseding merged work.