feat: implement AI-assisted rename prompting feature

- Added data model for AI-assisted renaming including structures for prompts, responses, and policies.
- Created implementation plan detailing the integration of Google Genkit into the CLI for renaming tasks.
- Developed quickstart guide for setting up and using the new AI rename functionality.
- Documented research decisions regarding Genkit orchestration and prompt composition.
- Established tasks for phased implementation, including setup, foundational work, and user stories.
- Implemented contract tests to ensure AI rename policies and ledger metadata are correctly applied.
- Developed integration tests for validating AI rename flows, including preview, apply, and undo functionalities.
- Added tooling to pin Genkit dependency for consistent builds.

internal/output/plain.go

@@ -3,6 +3,7 @@ package output
 import (
 	"fmt"
 	"io"
+	"strings"
 )
 
 // plainFormatter emits one entry per line suitable for piping into other tools.
@@ -26,3 +27,41 @@ func (plainFormatter) WriteSummary(w io.Writer, summary Summary) error {
 	_, err := fmt.Fprintln(w, DefaultSummaryLine(summary))
 	return err
 }
+
+// WriteAIPlanDebug emits prompt hashes and warnings to the provided writer.
+func WriteAIPlanDebug(w io.Writer, promptHash string, warnings []string) {
+	if w == nil {
+		return
+	}
+	if promptHash != "" {
+		fmt.Fprintf(w, "Prompt hash: %s\n", promptHash)
+	}
+	for _, warning := range warnings {
+		if strings.TrimSpace(warning) == "" {
+			continue
+		}
+		fmt.Fprintf(w, "%s\n", warning)
+	}
+}
+
+// PolicyViolationMessage describes a single policy failure for display purposes.
+type PolicyViolationMessage struct {
+	Original string
+	Proposed string
+	Rule     string
+	Message  string
+}
+
+// WritePolicyViolations prints detailed policy failure information to the writer.
+func WritePolicyViolations(w io.Writer, violations []PolicyViolationMessage) {
+	if w == nil {
+		return
+	}
+	for _, violation := range violations {
+		rule := violation.Rule
+		if rule == "" {
+			rule = "policy"
+		}
+		fmt.Fprintf(w, "Policy violation (%s): %s -> %s (%s)\n", rule, violation.Original, violation.Proposed, violation.Message)
+	}
+}