Merge feature/source-proxy: 让被 CF/格式问题挡住的源真正可用

两件事都在回答同一个问题——为什么配了源却用不了：

- trae 源在流式下把模型打印的 tool_call 当纯文本透传，客户端收到
  finish_reason "stop" + 一段文本，agent 循环当场终止
- justwoker/tabitoken 坐在 Cloudflare 后面，直连 403，必须走代理 +
  浏览器 UA；但全局 env 代理会把 trae/localzen 等内网源也绕出去

因此引入 per-source proxy_url：指定的源走专属代理，未指定的保持直连。

internal/config/config.go

@@ -47,15 +47,19 @@ type Model struct {
 
 // Source describes a single upstream LLM provider.
 type Source struct {
-	Name          string                 `yaml:"name" json:"name"`
-	BaseURL       string                 `yaml:"base_url" json:"base_url"`
-	APIKey        string                 `yaml:"api_key" json:"api_key"`
-	APIKeyEnv     string                 `yaml:"api_key_env,omitempty" json:"-"` // reference to an env var holding the key (overrides api_key)
-	Adapter       string                 `yaml:"adapter" json:"adapter"`
-	Endpoint      string                 `yaml:"endpoint" json:"endpoint,omitempty"`             // chat endpoint override
-	ImageEndpoint string                 `yaml:"image_endpoint" json:"image_endpoint,omitempty"` // image endpoint override
-	Models        []Model                `yaml:"models" json:"models"`
-	Headers       map[string]string      `yaml:"headers" json:"headers,omitempty"`
+	Name          string            `yaml:"name" json:"name"`
+	BaseURL       string            `yaml:"base_url" json:"base_url"`
+	APIKey        string            `yaml:"api_key" json:"api_key"`
+	APIKeyEnv     string            `yaml:"api_key_env,omitempty" json:"-"` // reference to an env var holding the key (overrides api_key)
+	Adapter       string            `yaml:"adapter" json:"adapter"`
+	Endpoint      string            `yaml:"endpoint" json:"endpoint,omitempty"`             // chat endpoint override
+	ImageEndpoint string            `yaml:"image_endpoint" json:"image_endpoint,omitempty"` // image endpoint override
+	Models        []Model           `yaml:"models" json:"models"`
+	Headers       map[string]string `yaml:"headers" json:"headers,omitempty"`
+	// ProxyURL routes this source's HTTP(S) traffic through an explicit proxy
+	// (e.g. http://127.0.0.1:7890). Empty = direct connection. Needed for
+	// upstreams behind geo/IP blocks that only respond through a proxy.
+	ProxyURL      string                 `yaml:"proxy_url" json:"proxy_url,omitempty"`
 	Meta          map[string]interface{} `yaml:"meta" json:"meta,omitempty"`
 	Temperature   float64                `yaml:"temperature" json:"temperature,omitempty"`
 	MaxTokens     int                    `yaml:"max_tokens" json:"max_tokens,omitempty"`
@@ -328,13 +332,15 @@ type RuntimeConfig struct {
 // name and api_key) so the WebUI can spin up multiple key-bearing sources
 // from one shared template.
 type SourceTemplate struct {
-	Name          string                 `json:"name"`
-	BaseURL       string                 `json:"base_url"`
-	Adapter       string                 `json:"adapter"`
-	Endpoint      string                 `json:"endpoint,omitempty"`
-	ImageEndpoint string                 `json:"image_endpoint,omitempty"`
-	Models        []Model                `json:"models"`
-	Headers       map[string]string      `json:"headers,omitempty"`
+	Name          string            `json:"name"`
+	BaseURL       string            `json:"base_url"`
+	Adapter       string            `json:"adapter"`
+	Endpoint      string            `json:"endpoint,omitempty"`
+	ImageEndpoint string            `json:"image_endpoint,omitempty"`
+	Models        []Model           `json:"models"`
+	Headers       map[string]string `json:"headers,omitempty"`
+	// ProxyURL routes this source's HTTP(S) traffic through an explicit proxy.
+	ProxyURL      string                 `json:"proxy_url,omitempty"`
 	Meta          map[string]interface{} `json:"meta,omitempty"`
 	Temperature   float64                `json:"temperature,omitempty"`
 	MaxTokens     int                    `json:"max_tokens,omitempty"`

internal/lua/adapters/trae.lua

@@ -46,9 +46,6 @@ end
 -- Returns (tool_calls_array_or_nil, content_with_blocks_removed).
 local function parse_text_tool_calls(content)
     if type(content) ~= "string" or content == "" then return nil, content end
-    if not (content:find("<tool_call", 1, true) or content:find("<toolcall", 1, true)) then
-        return nil, content
-    end
 
     local tcs = {}
     local idx = 0
@@ -88,11 +85,31 @@ local function parse_text_tool_calls(content)
     collect("<tool_call[^>]*>%s*(.-)%s*</tool_call%s*>")
     collect("<toolcall[^>]*>%s*(.-)%s*</toolcall%s*>")
 
+    -- Legacy / mimicked form: models that saw past assistant turns folded as
+    --   [Called tool: name({...})]
+    -- tend to emit the same shape instead of a real  block. Recover it so
+    -- the agent loop keeps working; otherwise the client receives plain text
+    -- where a structured tool call should be. Capture the name and the JSON
+    -- object literal independently (the JSON is the only {...} run here).
+    if #tcs == 0 and content:find("%[Called tool") then
+        for name, argsraw in content:gmatch("%[Called tool%s*:%s*([%w_%-%.]+)%s*%((%b{})%s*%)%s*%]") do
+            local aok, decoded = pcall(json.decode, argsraw)
+            idx = idx + 1
+            table.insert(tcs, {
+                id = "call_legacy_" .. idx,
+                type = "function",
+                name = name,
+                arguments = aok and decoded or {}
+            })
+        end
+    end
+
     if #tcs == 0 then return nil, content end
 
     -- drop the blocks from user-visible content; keep any surrounding prose
     local stripped = content:gsub("<tool_call[^>]*>%s*.-%s*</tool_call%s*>", "")
     stripped = stripped:gsub("<toolcall[^>]*>%s*.-%s*</toolcall%s*>", "")
+    stripped = stripped:gsub("%[Called tool%s*:%s*[%w_%-%.]+%s*%(%b{}%s*%)%s*%]", "")
     stripped = stripped:gsub("^%s+", ""):gsub("%s+$", "")
     return tcs, stripped
 end

internal/provider/provider.go

@@ -13,6 +13,7 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/url"
 	"strconv"
 	"strings"
 	"sync"
@@ -24,6 +25,20 @@ import (
 	"llmsproxy/internal/types"
 )
 
+// proxyFor picks the transport proxy for one source. An explicit per-source
+// proxy_url wins (e.g. clash on 127.0.0.1:7890 for a geo-blocked upstream);
+// otherwise fall back to the process-wide env proxy, which is direct by
+// default.
+func proxyFor(cfg config.Source) func(*http.Request) (*url.URL, error) {
+	if cfg.ProxyURL != "" {
+		proxyURL, err := url.Parse(cfg.ProxyURL)
+		if err == nil {
+			return http.ProxyURL(proxyURL)
+		}
+	}
+	return http.ProxyFromEnvironment
+}
+
 // ---- per-(source,model) scheduling state ----
 
 // ModelState is the scheduling state of one (source, model) pair: a soft
@@ -388,8 +403,11 @@ func New(cfg config.Source, vm *lua.VM) *Provider {
 	// Shared transport: ResponseHeaderTimeout bounds how long we wait for the
 	// first response byte (applies to both paths); the stream client has no
 	// client-level Timeout so the SSE body can run past the header timeout.
+	// A per-source ProxyURL (e.g. clash on 127.0.0.1:7890) overrides the
+	// process-wide env proxy for upstreams that are geo/IP-blocked; sources
+	// without one keep http.ProxyFromEnvironment (direct by default).
 	tr := &http.Transport{
-		Proxy:                 http.ProxyFromEnvironment,
+		Proxy:                 proxyFor(cfg),
 		DialContext:           (&net.Dialer{Timeout: 30 * time.Second, KeepAlive: 30 * time.Second}).DialContext,
 		ForceAttemptHTTP2:     true,
 		MaxIdleConns:          100,