feat(providers): Moonshot AI provider + extract shared OpenAI-compat helpers

- Add MoonshotProvider and MoonshotCodeProvider (OpenAI-compatible)
- Extract `fetch_openai_models()` and `build_openai_llm()` shared functions,
  deduplicating model-listing and client construction across OpenAI,
  OpenRouter, DeepSeek, LM Studio, and Z.AI providers
- Add `lists_models` field to `ProviderUiMeta` — drives frontend model
  picker dynamically instead of hardcoded `type_id` list
- Port DeepSeek, LM Studio, OpenRouter model listing to `fetch_openai_models`
- Set `lists_models: true` on Z.AI provider (missed in prior pass)

feat(mcp): named key placeholders {SECRET:name}/{ENV:name} in connector URLs

- `apply_key_placeholder` now accepts an `env` map alongside `api_key`
- Named tokens resolve from the connector's described `env[]` fields,
  with `{SECRET:name}` falling back to `api_key` for backward compat
- Replace `substitute_secret_tokens` with `substitute_named_tokens`
- Unresolved tokens are left in place (visible misconfig) rather than
  silently producing a wrong URL

fix(ui): connector detail hides generic API key when schema has secret

fix(ui): model picker uses `lists_models` from provider types endpoint

web/components/models-llm.js

@@ -44,6 +44,7 @@ export class ModelsLlmSection extends LightElement {
     onback:          { attribute: false },
     _models:         { state: true },
     _providers:      { state: true },
+    _providerTypes:  { state: true },
     _modal:          { state: true },
     _saving:         { state: true },
     _error:          { state: true },
@@ -61,6 +62,7 @@ export class ModelsLlmSection extends LightElement {
     this.onback          = null;
     this._models         = [];
     this._providers      = [];
+    this._providerTypes  = [];
     this._modal          = null;
     this._saving         = false;
     this._error          = null;
@@ -80,14 +82,17 @@ export class ModelsLlmSection extends LightElement {
 
   async _load() {
     try {
-      const [modelsRes, providersRes] = await Promise.all([
+      const [modelsRes, providersRes, typesRes] = await Promise.all([
         fetch('/api/llm/models'),
         fetch('/api/llm/providers'),
+        fetch('/api/llm/providers/types'),
       ]);
       if (!modelsRes.ok)    throw new Error(`models: HTTP ${modelsRes.status}`);
       if (!providersRes.ok) throw new Error(`providers: HTTP ${providersRes.status}`);
-      this._models    = await modelsRes.json();
-      this._providers = await providersRes.json();
+      if (!typesRes.ok)     throw new Error(`provider types: HTTP ${typesRes.status}`);
+      this._models        = await modelsRes.json();
+      this._providers     = await providersRes.json();
+      this._providerTypes = await typesRes.json();
     } catch (e) {
       this._error = e.message;
     }
@@ -157,9 +162,9 @@ export class ModelsLlmSection extends LightElement {
     this._pickedProvider = provider;
     this._reasoningMode  = null;
 
-    const hasModelPicker = ['openrouter', 'ollama', 'lm_studio', 'deepseek', 'zai'].includes(provider.type);
+    const typeMeta = this._providerTypes.find(t => t.type_id === provider.type);
 
-    if (hasModelPicker) {
+    if (typeMeta?.lists_models) {
       this._orForm   = emptyOrForm();
       this._orSearch = '';
       this._orModels = [];