feat: use Google Gemini as default vision backend, make provider configurable

- Plugin options: baseURL, apiKey, model, providerID, visionModels
- Default: Google Gemini OpenAI-compatible endpoint, gemini-2.5-flash
- Support {env:VAR} templates and GEMINI_API_KEY fallback
- Legacy fallback to ludmila-ai provider block for existing setups
- vision.md subagent now uses google/gemini-2.5-flash

examples/opencode.json

@@ -2,31 +2,31 @@
   "$schema": "https://opencode.ai/config.json",
   "plugin": [
     "opencode-browser",
-    "git+https://git.totmin.ru/en2zmax/vision-bridge.git"
+    [
+      "git+https://git.totmin.ru/en2zmax/vision-bridge.git",
+      {
+        "baseURL": "https://generativelanguage.googleapis.com/v1beta/openai",
+        "apiKey": "{env:GEMINI_API_KEY}",
+        "model": "gemini-2.5-flash"
+      }
+    ]
   ],
   "provider": {
-    "ludmila-ai": {
-      "npm": "@ai-sdk/openai-compatible",
-      "name": "Ludmila AI",
+    "google": {
+      "npm": "@ai-sdk/google",
+      "name": "Google",
       "options": {
-        "baseURL": "https://ai.totmin.ru/v1",
-        "apiKey": "<ЗАМЕНИТЕ_НА_ВАШ_API_КЛЮЧ>"
+        "apiKey": "{env:GEMINI_API_KEY}"
       },
       "models": {
-        "gemini/gemini-2.5-flash": {
-          "attachment": true,
-          "limit": {
-            "context": 1048576,
-            "output": 65536
-          }
-        }
+        "gemini-2.5-flash": {}
       }
     }
   },
   "agent": {
     "vision": {
       "mode": "subagent",
-      "model": "ludmila-ai/gemini/gemini-2.5-flash",
+      "model": "google/gemini-2.5-flash",
       "description": "Анализ изображений и скриншотов (OCR текста или разбор UI)",
       "permission": {
         "read": "allow",