feat: add Nous Portal API key provider (#644)

Add support for using Nous Portal via a direct API key, mirroring
how OpenRouter and other API-key providers work. This gives users a
simpler alternative to the OAuth device-code flow when they already
have a Nous API key.

Changes:
- Add 'nous-api' to PROVIDER_REGISTRY as an api_key provider
  pointing to https://inference-api.nousresearch.com/v1
- Add NOUS_API_KEY and NOUS_BASE_URL to OPTIONAL_ENV_VARS
- Add NOUS_API_BASE_URL / NOUS_API_CHAT_URL to hermes_constants
- Add 'Nous Portal API key' as first option in setup wizard
- Add provider aliases (nous_api, nousapi, nous-portal-api)
- Add test for nous-api runtime provider resolution

Closes #644

hermes_cli/config.py

@@ -207,6 +207,22 @@ REQUIRED_ENV_VARS = {}
 # Optional environment variables that enhance functionality
 OPTIONAL_ENV_VARS = {
     # ── Provider (handled in provider selection, not shown in checklists) ──
+    "NOUS_API_KEY": {
+        "description": "Nous Portal API key (direct API key access to Nous inference)",
+        "prompt": "Nous Portal API key",
+        "url": "https://portal.nousresearch.com",
+        "password": True,
+        "category": "provider",
+        "advanced": True,
+    },
+    "NOUS_BASE_URL": {
+        "description": "Nous Portal base URL override",
+        "prompt": "Nous Portal base URL (leave empty for default)",
+        "url": None,
+        "password": False,
+        "category": "provider",
+        "advanced": True,
+    },
     "OPENROUTER_API_KEY": {
         "description": "OpenRouter API key (for vision, web scraping helpers, and MoA)",
         "prompt": "OpenRouter API key",