fix(auth): add Codex OAuth accounts as distinct pool entries

hermes auth add openai-codex now creates an independent
manual:device_code pool entry per account instead of routing through
the singleton _save_codex_tokens save path, which collapsed every
added account into the latest login (the second add overwrote the
first account's singleton-mirrored device_code entry). This is the
add-path half of #39236; PR #39243 (already on this branch) fixes the
re-auth half.

manual:device_code entries refresh from their own token pair
(_sync_codex_entry_from_auth_store only adopts the singleton for
source=="device_code"), so they need no providers.openai-codex
shadow. Adding the first credential marks openai-codex active (the
singleton path did this implicitly) so the setup wizard's
get_active_provider() check still passes; subsequent adds leave the
active provider untouched.

Adds SOURCE_MANUAL_DEVICE_CODE constant and a regression test that two
distinct accounts keep distinct token pairs. Updates two existing add
tests to the pool-only behavior.

Co-authored-by: glesperance <info@glesperance.com>

hermes_cli/auth.py

@@ -1182,6 +1182,24 @@ def _store_provider_state(
         auth_store["active_provider"] = provider_id
 
 
+def mark_provider_active_if_unset(provider_id: str) -> None:
+    """Set ``active_provider`` to *provider_id* only when none is set yet.
+
+    Used by ``hermes auth add`` OAuth paths that create credential-pool
+    entries directly (no singleton ``providers.<id>`` block). Adding the
+    very first credential for a provider should make it the active provider
+    so the setup wizard's ``_model_section_has_credentials()`` check (which
+    consults ``get_active_provider()``) does not report "No inference
+    provider configured". Subsequent adds for an already-active setup leave
+    the user's chosen active provider untouched.
+    """
+    with _auth_store_lock():
+        auth_store = _load_auth_store()
+        if not (auth_store.get("active_provider") or "").strip():
+            auth_store["active_provider"] = provider_id
+            _save_auth_store(auth_store)
+
+
 def is_known_auth_provider(provider_id: str) -> bool:
     normalized = (provider_id or "").strip().lower()
     return normalized in PROVIDER_REGISTRY or normalized in SERVICE_PROVIDER_NAMES

hermes_cli/auth_commands.py

@@ -13,6 +13,7 @@ from agent.credential_pool import (
     AUTH_TYPE_OAUTH,
     CUSTOM_POOL_PREFIX,
     SOURCE_MANUAL,
+    SOURCE_MANUAL_DEVICE_CODE,
     STATUS_EXHAUSTED,
     STRATEGY_FILL_FIRST,
     STRATEGY_ROUND_ROBIN,
@@ -312,15 +313,35 @@ def auth_add_command(args) -> None:
             creds["tokens"]["access_token"],
             _oauth_default_label(provider, len(pool.entries()) + 1),
         )
-        auth_mod._save_codex_tokens(
-            creds["tokens"],
-            last_refresh=creds.get("last_refresh"),
+        # Add a distinct, self-contained pool entry per account (matching the
+        # xai-oauth / google-gemini-cli / qwen-oauth patterns) instead of
+        # routing through the singleton ``_save_codex_tokens`` save path.
+        # The singleton round-trip collapsed every added account into the
+        # latest login: a second ``hermes auth add openai-codex`` overwrote
+        # the first account's singleton-mirrored ``device_code`` entry rather
+        # than creating an independent one (#39236). ``manual:device_code``
+        # entries refresh from their own token pair, so they need no singleton
+        # shadow.
+        entry = PooledCredential(
+            provider=provider,
+            id=uuid.uuid4().hex[:6],
             label=label,
+            auth_type=AUTH_TYPE_OAUTH,
+            priority=0,
+            source=SOURCE_MANUAL_DEVICE_CODE,
+            access_token=creds["tokens"]["access_token"],
+            refresh_token=creds["tokens"].get("refresh_token"),
+            base_url=creds.get("base_url"),
+            last_refresh=creds.get("last_refresh"),
         )
-        pool = load_pool(provider)
-        entry = next((item for item in pool.entries() if item.source == "device_code"), None)
-        shown_label = entry.label if entry is not None else label
-        print(f'Saved {provider} OAuth device-code credentials: "{shown_label}"')
+        first_credential = not pool.entries()
+        pool.add_entry(entry)
+        # Adding the first Codex credential should make it the active provider
+        # (the old singleton save path did this implicitly via
+        # _save_provider_state). Subsequent adds leave the active provider as-is.
+        if first_credential:
+            auth_mod.mark_provider_active_if_unset(provider)
+        print(f'Added {provider} OAuth credential #{len(pool.entries())}: "{entry.label}"')
         return
 
     if provider == "xai-oauth":