follow-up: align ingress, atomic paths, and channel tests with credential semantics (#33733)

Merged via squash.

Prepared head SHA: c290c2ab6a
Co-authored-by: joshavant <830519+joshavant@users.noreply.github.com>
Co-authored-by: joshavant <830519+joshavant@users.noreply.github.com>
Reviewed-by: @joshavant

docs/auth-credential-semantics.md

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+# Auth Credential Semantics
+
+This document defines the canonical credential eligibility and resolution semantics used across:
+
+- `resolveAuthProfileOrder`
+- `resolveApiKeyForProfile`
+- `models status --probe`
+- `doctor-auth`
+
+The goal is to keep selection-time and runtime behavior aligned.
+
+## Stable Reason Codes
+
+- `ok`
+- `missing_credential`
+- `invalid_expires`
+- `expired`
+- `unresolved_ref`
+
+## Token Credentials
+
+Token credentials (`type: "token"`) support inline `token` and/or `tokenRef`.
+
+### Eligibility rules
+
+1. A token profile is ineligible when both `token` and `tokenRef` are absent.
+2. `expires` is optional.
+3. If `expires` is present, it must be a finite number greater than `0`.
+4. If `expires` is invalid (`NaN`, `0`, negative, non-finite, or wrong type), the profile is ineligible with `invalid_expires`.
+5. If `expires` is in the past, the profile is ineligible with `expired`.
+6. `tokenRef` does not bypass `expires` validation.
+
+### Resolution rules
+
+1. Resolver semantics match eligibility semantics for `expires`.
+2. For eligible profiles, token material may be resolved from inline value or `tokenRef`.
+3. Unresolvable refs produce `unresolved_ref` in `models status --probe` output.
+
+## Legacy-Compatible Messaging
+
+For script compatibility, probe errors keep this first line unchanged:
+
+`Auth profile credentials are missing or expired.`
+
+Human-friendly detail and stable reason codes may be added on subsequent lines.