fix: three CLI quality-of-life fixes (#10468, #10230, #10526, #9545) (#10599)

Three independent fixes batched together:

1. hermes auth add crashes on non-interactive stdin (#10468)
   input() for the label prompt was called without checking isatty().
   In scripted/CI environments this raised EOFError. Fix: check
   sys.stdin.isatty() and fall back to the computed default label.

2. Subcommand help prints twice (#10230)
   'hermes dashboard -h' printed help text twice because the
   SystemExit(0) from argparse was caught by the fallback retry
   logic, which re-parsed and printed help again. Fix: re-raise
   SystemExit with code 0 (help/version) immediately.

3. Duplicate entries in /model picker (#10526, #9545)
   - Kimi showed 2x because kimi-coding and kimi-coding-cn both
     mapped to the same models.dev ID. Fix: track seen mdev_ids
     and skip aliases.
   - Providers could show 2-3x from case-variant slugs across the
     four loading paths. Fix: normalize all seen_slugs membership
     checks and insertions to lowercase.

Closes #10468, #10230, #10526, #9545

hermes_cli/auth_commands.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 from getpass import getpass
 import math
+import sys
 import time
 from types import SimpleNamespace
 import uuid
@@ -160,7 +161,10 @@ def auth_add_command(args) -> None:
         default_label = _api_key_default_label(len(pool.entries()) + 1)
         label = (getattr(args, "label", None) or "").strip()
         if not label:
-            label = input(f"Label (optional, default: {default_label}): ").strip() or default_label
+            if sys.stdin.isatty():
+                label = input(f"Label (optional, default: {default_label}): ").strip() or default_label
+            else:
+                label = default_label
         entry = PooledCredential(
             provider=provider,
             id=uuid.uuid4().hex[:6],