Improve thinking/tool signature handling for Claude and Gemini requests

Prefer cached signatures and avoid injecting dummy thinking blocks; instead remove unsigned thinking blocks and add a skip sentinel for tool calls without a valid signature. Generate stable session IDs from the first user message, apply schema cleaning only for Claude models, and reorder thinking parts so thinking appears first. For Gemini, remove thinking blocks and attach a skip sentinel to function calls. Simplify response handling by passing raw function args through (remove special Bash conversion). Update and add tests to reflect the new behavior.

These changes prevent rejected dummy signatures, improve compatibility with Antigravity’s signature validation, provide more stable session IDs for conversation grouping, and make request/response translation more robust.

internal/translator/antigravity/claude/antigravity_claude_response_test.go

@@ -8,79 +8,6 @@ import (
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/cache"
 )
 
-func TestConvertBashCommandToCmdField(t *testing.T) {
-	tests := []struct {
-		name     string
-		input    string
-		expected string
-	}{
-		{
-			name:     "basic command to cmd conversion",
-			input:    `{"command": "git diff"}`,
-			expected: `{"cmd":"git diff"}`,
-		},
-		{
-			name:     "already has cmd field - no change",
-			input:    `{"cmd": "git diff"}`,
-			expected: `{"cmd": "git diff"}`,
-		},
-		{
-			name:     "both cmd and command - keep cmd only",
-			input:    `{"command": "git diff", "cmd": "ls"}`,
-			expected: `{"command": "git diff", "cmd": "ls"}`, // no change when cmd exists
-		},
-		{
-			name:     "command with special characters in value",
-			input:    `{"command": "echo \"command\": test"}`,
-			expected: `{"cmd":"echo \"command\": test"}`,
-		},
-		{
-			name:     "command with nested quotes",
-			input:    `{"command": "bash -c 'echo \"hello\"'"}`,
-			expected: `{"cmd":"bash -c 'echo \"hello\"'"}`,
-		},
-		{
-			name:     "command with newlines",
-			input:    `{"command": "echo hello\necho world"}`,
-			expected: `{"cmd":"echo hello\necho world"}`,
-		},
-		{
-			name:     "empty command value",
-			input:    `{"command": ""}`,
-			expected: `{"cmd":""}`,
-		},
-		{
-			name:     "command with other fields - preserves them",
-			input:    `{"command": "git diff", "timeout": 30}`,
-			expected: `{ "timeout": 30,"cmd":"git diff"}`,
-		},
-		{
-			name:     "invalid JSON - returns unchanged",
-			input:    `{invalid json`,
-			expected: `{invalid json`,
-		},
-		{
-			name:     "empty object",
-			input:    `{}`,
-			expected: `{}`,
-		},
-		{
-			name:     "no command field",
-			input:    `{"restart": true}`,
-			expected: `{"restart": true}`,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := convertBashCommandToCmdField(tt.input)
-			if result != tt.expected {
-				t.Errorf("convertBashCommandToCmdField(%q) = %q, want %q", tt.input, result, tt.expected)
-			}
-		})
-	}
-}
-
 // ============================================================================
 // Signature Caching Tests
 // ============================================================================
@@ -354,7 +281,7 @@ func TestDeriveSessionIDFromRequest(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			result := deriveSessionIDFromRequest(tt.input)
+			result := deriveSessionID(tt.input)
 			if tt.wantEmpty && result != "" {
 				t.Errorf("Expected empty session ID, got '%s'", result)
 			}
@@ -368,8 +295,8 @@ func TestDeriveSessionIDFromRequest(t *testing.T) {
 func TestDeriveSessionIDFromRequest_Deterministic(t *testing.T) {
 	input := []byte(`{"messages": [{"role": "user", "content": "Same message"}]}`)
 
-	id1 := deriveSessionIDFromRequest(input)
-	id2 := deriveSessionIDFromRequest(input)
+	id1 := deriveSessionID(input)
+	id2 := deriveSessionID(input)
 
 	if id1 != id2 {
 		t.Errorf("Session ID should be deterministic: '%s' != '%s'", id1, id2)
@@ -380,8 +307,8 @@ func TestDeriveSessionIDFromRequest_DifferentMessages(t *testing.T) {
 	input1 := []byte(`{"messages": [{"role": "user", "content": "Message A"}]}`)
 	input2 := []byte(`{"messages": [{"role": "user", "content": "Message B"}]}`)
 
-	id1 := deriveSessionIDFromRequest(input1)
-	id2 := deriveSessionIDFromRequest(input2)
+	id1 := deriveSessionID(input1)
+	id2 := deriveSessionID(input2)
 
 	if id1 == id2 {
 		t.Error("Different messages should produce different session IDs")