feat: add z.ai/GLM, Kimi/Moonshot, MiniMax as first-class providers

Adds 4 new direct API-key providers (zai, kimi-coding, minimax, minimax-cn)
to the inference provider system. All use standard OpenAI-compatible
chat/completions endpoints with Bearer token auth.

Core changes:
- auth.py: Extended ProviderConfig with api_key_env_vars and base_url_env_var
  fields. Added providers to PROVIDER_REGISTRY. Added provider aliases
  (glm, z-ai, zhipu, kimi, moonshot). Added auto-detection of API-key
  providers in resolve_provider(). Added resolve_api_key_provider_credentials()
  and get_api_key_provider_status() helpers.
- runtime_provider.py: Added generic API-key provider branch in
  resolve_runtime_provider() — any provider with auth_type='api_key'
  is automatically handled.
- main.py: Added providers to hermes model menu with generic
  _model_flow_api_key_provider() flow. Updated _has_any_provider_configured()
  to check all provider env vars. Updated argparse --provider choices.
- setup.py: Added providers to setup wizard with API key prompts and
  curated model lists.
- config.py: Added env vars (GLM_API_KEY, KIMI_API_KEY, MINIMAX_API_KEY,
  etc.) to OPTIONAL_ENV_VARS.
- status.py: Added API key display and provider status section.
- doctor.py: Added connectivity checks for each provider endpoint.
- cli.py: Updated provider docstrings.

Docs: Updated README.md, .env.example, cli-config.yaml.example,
cli-commands.md, environment-variables.md, configuration.md.

Tests: 50 new tests covering registry, aliases, resolution, auto-detection,
credential resolution, and runtime provider dispatch.

Inspired by PR #33 (numman-ali) which proposed a provider registry approach.
Credit to tars90percent (PR #473) and manuelschipper (PR #420) for related
provider improvements merged earlier in this changeset.

cli-config.yaml.example

@@ -13,6 +13,10 @@ model:
   #   "auto"       - Use Nous Portal if logged in, otherwise OpenRouter/env vars (default)
   #   "openrouter" - Always use OpenRouter API key from OPENROUTER_API_KEY
   #   "nous"       - Always use Nous Portal (requires: hermes login)
+  #   "zai"        - Use z.ai / ZhipuAI GLM models (requires: GLM_API_KEY)
+  #   "kimi-coding"- Use Kimi / Moonshot AI models (requires: KIMI_API_KEY)
+  #   "minimax"    - Use MiniMax global endpoint (requires: MINIMAX_API_KEY)
+  #   "minimax-cn" - Use MiniMax China endpoint (requires: MINIMAX_CN_API_KEY)
   # Can also be overridden with --provider flag or HERMES_INFERENCE_PROVIDER env var.
   provider: "auto"