**refactor(cliproxy, config): remove vertex-compat flow, streamline Vertex API key handling**

- Removed `vertex-compat` executor and related configuration.
- Consolidated Vertex compatibility checks into `vertex` handling with `apikey`-based model resolution.
- Streamlined model generation logic for Vertex API key entries.

config.example.yaml

@@ -145,6 +145,19 @@ ws-auth: false
 #      - name: "moonshotai/kimi-k2:free" # The actual model name.
 #        alias: "kimi-k2" # The alias used in the API.
 
+# Vertex API keys (Vertex-compatible endpoints, use API key + base URL)
+#vertex-api-key:
+#  - api-key: "vk-123..."                        # x-goog-api-key header
+#    base-url: "https://example.com/api"         # e.g. https://zenmux.ai/api
+#    proxy-url: "socks5://proxy.example.com:1080" # optional per-key proxy override
+#    headers:
+#      X-Custom-Header: "custom-value"
+#    models:                                     # optional: map aliases to upstream model names
+#      - name: "gemini-2.0-flash"                # upstream model name
+#        alias: "vertex-flash"                   # client-visible alias
+#      - name: "gemini-1.5-pro"
+#        alias: "vertex-pro"
+
 #payload: # Optional payload configuration
 #  default: # Default rules only set parameters when they are missing in the payload.
 #    - models: