fix(phase-1): redact API key query params from log output and add mutex thread-safety to providers map

internal/providers/gemini.go

@@ -375,7 +375,7 @@ func (p *GeminiProvider) ChatCompletion(ctx context.Context, req *models.Unified
 	}
 
 	url := fmt.Sprintf("%s/models/%s:generateContent?key=%s", baseURL, req.Model, p.apiKey)
-	fmt.Printf("[Gemini] POST %s\n", url)
+	fmt.Printf("[Gemini] POST %s\n", SanitizeURL(url))
 
 	resp, err := p.client.R().
 		SetContext(ctx).
@@ -633,7 +633,7 @@ func (p *GeminiProvider) ChatCompletionStream(ctx context.Context, req *models.U
 
 	// Use streamGenerateContent for streaming
 	url := fmt.Sprintf("%s/models/%s:streamGenerateContent?key=%s", baseURL, req.Model, p.apiKey)
-	fmt.Printf("[Gemini-Stream] POST %s\n", url)
+	fmt.Printf("[Gemini-Stream] POST %s\n", SanitizeURL(url))
 
 	resp, err := p.client.R().
 		SetContext(ctx).

internal/providers/helpers.go

@@ -5,11 +5,20 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"regexp"
 	"strings"
 
 	"gophergate/internal/models"
 )
 
+var keySanitizeRegex = regexp.MustCompile(`(?i)(key|api_key|secret)=[^&]+`)
+
+// SanitizeURL strips sensitive key query parameters from URLs before logging.
+func SanitizeURL(rawURL string) string {
+	return keySanitizeRegex.ReplaceAllString(rawURL, "$1=REDACTED")
+}
+
+
 func sanitizeFunctionName(name string) string {
 	var sb strings.Builder
 	for _, ch := range name {