feat: provider modules — ProviderProfile ABC, 30 providers, fetch_models, transport single-path

feat: provider modules — ProviderProfile ABC, 29 providers, fetch_models, transport single-path

Introduces providers/ as the single source of truth for every inference
provider. All 29 providers declared with correct data cross-checked against
auth.py, runtime_provider.py and auxiliary_client.py.

Rebased onto main (30307a980). Incorporates post-salvage fixes from
56724147e (gmi aux model google/gemini-3.1-flash-lite-preview, already set in providers/gmi.py).

hermes_cli/config.py

@@ -4252,3 +4252,45 @@ def config_command(args):
         print("  hermes config path      Show config file path")
         print("  hermes config env-path  Show .env file path")
         sys.exit(1)
+
+
+# ── Profile-driven env var injection ─────────────────────────────────────────
+# Any provider registered in providers/ with auth_type="api_key" automatically
+# gets its env_vars exposed in OPTIONAL_ENV_VARS without editing this file.
+# Runs once at import time.
+
+_profile_env_vars_injected = False
+
+
+def _inject_profile_env_vars() -> None:
+    """Populate OPTIONAL_ENV_VARS from provider profiles not already listed.
+
+    Called once at module load time. Idempotent — repeated calls are no-ops.
+    """
+    global _profile_env_vars_injected
+    if _profile_env_vars_injected:
+        return
+    _profile_env_vars_injected = True
+    try:
+        from providers import list_providers
+        for _pp in list_providers():
+            if _pp.auth_type not in ("api_key",):
+                continue
+            for _var in _pp.env_vars:
+                if _var in OPTIONAL_ENV_VARS:
+                    continue
+                _is_key = not _var.endswith("_BASE_URL") and not _var.endswith("_URL")
+                OPTIONAL_ENV_VARS[_var] = {
+                    "description": f"{_pp.display_name or _pp.name} {'API key' if _is_key else 'base URL override'}",
+                    "prompt": f"{_pp.display_name or _pp.name} {'API key' if _is_key else 'base URL (leave empty for default)'}",
+                    "url": _pp.signup_url or None,
+                    "password": _is_key,
+                    "category": "provider",
+                    "advanced": True,
+                }
+    except Exception:
+        pass
+
+
+# Eagerly inject so that OPTIONAL_ENV_VARS is fully populated at import time.
+_inject_profile_env_vars()