refactor(testgen): update Go prompt to enforce unit + live test pattern

- Modify user message to reference new pattern in system prompt
- Revise Go test prompt for exact unit/live structure matching scaffold_test.go
- Update testgen_test.go to match new prompt prefix

cmd/testgen.go

@@ -124,8 +124,7 @@ func processTestgenFile(client *grok.Client, filePath, lang, systemPrompt, model
 		},
 		{
 			"role":    "user",
-			"content": fmt.Sprintf("Source file %s (%s):\n```%s\n%s\n```\n\nGenerate the language-appropriate test file.", filepath.Base(filePath), lang, codeLang, cleanSrc),
-		},
+			"content": fmt.Sprintf("Source file %s (%s):\n```%s\n%s\n```\n\nGenerate the test file using the new Unit + Live integration pattern described in the system prompt.", filepath.Base(filePath), lang, codeLang, cleanSrc)},
 	}
 
 	color.Yellow("🤖 Generating tests for %s → %s...", filepath.Base(filePath), filepath.Base(testPath))
@@ -193,21 +192,33 @@ func removeSourceComments(content, lang string) string {
 func getTestPrompt(lang string) string {
 	switch lang {
 	case "Go":
-		return `You are an expert Go testing specialist. Generate COMPLETE, production-ready unit tests for the provided Go source:
+		return `You are an expert Go test writer for the Grokkit project.
 
-- Table-driven with t.Run(subtest, func(t *testing.T)) and t.Parallel()
-- Match exact style of gmgauthier/grokkit/internal/version/version_test.go
-- Use t.Context() for ctx-aware tests
-- Modern Go 1.24+: slices.Contains/IndexFunc, maps.Keys, errors.Is/Join, any, etc.
-- Cover ALL public funcs/methods/fields: happy path, edges, errors, panics, zero values
-- Realistic inputs, no external deps/mocks unless code requires
-- func TestXxx(t *testing.T) { ... } only
+Generate a COMPLETE, production-ready *_test.go file that follows this EXACT pattern:
 
-Respond with ONLY the full *_test.go file:
-- Correct package name (infer from code)
-- Necessary imports
-- No benchmarks unless obvious perf func
-- NO prose, explanations, markdown, code blocks, or extra text. Pure Go test file.`
+1. Fast unit test(s) named TestXXX_Unit (or just TestXXX for the main test)
+   - Zero API calls
+   - Uses t.TempDir() + os.Chdir with proper defer restore (and error logging)
+   - Uses testify/assert and require
+   - Always runs instantly on "make test"
+
+2. Optional live integration test named TestXXX_Live
+   - Skipped by default with a clear t.Skip message showing the exact command to run it
+   - Only runs when the user passes -short
+   - Does real Grok API calls (exactly like the scaffold live test)
+   - Includes t.Log messages so it never looks hung
+
+Match the style of cmd/scaffold_test.go exactly:
+- Clear t.Logf messages
+- Table-driven where it makes sense
+- Proper temp-dir isolation
+- No unused imports
+- defer restore of working directory with error logging
+
+Return ONLY the full Go test file. No explanations, no markdown, no backticks, no extra text whatsoever.
+
+Current project style (match imports, helpers, error handling):
+{{.Context}}`
 	case "Python":
 		return `You are a pytest expert. Generate COMPLETE pytest unit tests for the Python source.
 

cmd/testgen_test.go

@@ -93,7 +93,7 @@ func TestGetTestPrompt(t *testing.T) {
 		lang       string
 		wantPrefix string
 	}{
-		{"Go", "You are an expert Go testing specialist."},
+		{"Go", "You are an expert Go test writer for the Grokkit project."},
 		{"Python", "You are a pytest expert."},
 		{"C", "You are a C unit testing expert using Check framework."},
 		{"C++", "You are a Google Test expert."},