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.

tests/contract/ai_policy_contract_test.go

@@ -0,0 +1,116 @@
+package contract
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	renamercmd "github.com/rogeecn/renamer/cmd"
+	"github.com/rogeecn/renamer/internal/ai/genkit"
+	"github.com/rogeecn/renamer/internal/ai/prompt"
+)
+
+type captureWorkflow struct {
+	request genkit.Request
+}
+
+func (c *captureWorkflow) Run(ctx context.Context, req genkit.Request) (genkit.Result, error) {
+	c.request = req
+	return genkit.Result{
+		Response: prompt.RenameResponse{
+			Items: []prompt.RenameItem{
+				{
+					Original: "alpha.txt",
+					Proposed: "proj_001_sample_file.txt",
+					Sequence: 1,
+				},
+			},
+			Model: "test-model",
+		},
+	}, nil
+}
+
+func TestAICommandAppliesNamingPoliciesToPrompt(t *testing.T) {
+	genkit.ResetWorkflowFactory()
+	stub := &captureWorkflow{}
+	genkit.OverrideWorkflowFactory(func(ctx context.Context, opts genkit.Options) (genkit.WorkflowRunner, error) {
+		return stub, nil
+	})
+	t.Cleanup(genkit.ResetWorkflowFactory)
+
+	rootDir := t.TempDir()
+	createPolicyTestFile(t, filepath.Join(rootDir, "alpha.txt"))
+
+	rootCmd := renamercmd.NewRootCommand()
+	var stdout, stderr bytes.Buffer
+	rootCmd.SetOut(&stdout)
+	rootCmd.SetErr(&stderr)
+	rootCmd.SetArgs([]string{
+		"ai",
+		"--path", rootDir,
+		"--dry-run",
+		"--naming-casing", "snake",
+		"--naming-prefix", "proj",
+		"--naming-allow-spaces",
+		"--naming-keep-order",
+		"--banned", "alpha",
+	})
+
+	if err := rootCmd.Execute(); err != nil {
+		if stdout.Len() > 0 {
+			t.Logf("stdout: %s", stdout.String())
+		}
+		if stderr.Len() > 0 {
+			t.Logf("stderr: %s", stderr.String())
+		}
+		t.Fatalf("command execute: %v", err)
+	}
+
+	req := stub.request
+	policies := req.Payload.Policies
+	if policies.Prefix != "proj" {
+		t.Fatalf("expected prefix proj, got %q", policies.Prefix)
+	}
+	if policies.Casing != "snake" {
+		t.Fatalf("expected casing snake, got %q", policies.Casing)
+	}
+	if !policies.AllowSpaces {
+		t.Fatalf("expected allow spaces flag to propagate")
+	}
+	if !policies.KeepOriginalOrder {
+		t.Fatalf("expected keep original order flag to propagate")
+	}
+	if len(policies.ForbiddenTokens) != 1 || policies.ForbiddenTokens[0] != "alpha" {
+		t.Fatalf("expected forbidden tokens to capture user list, got %#v", policies.ForbiddenTokens)
+	}
+
+	banned := req.Payload.BannedTerms
+	containsDefault := false
+	containsUser := false
+	for _, term := range banned {
+		switch term {
+		case "alpha":
+			containsUser = true
+		case "clickbait":
+			containsDefault = true
+		}
+	}
+	if !containsUser {
+		t.Fatalf("expected banned terms to include user-provided token")
+	}
+	if !containsDefault {
+		t.Fatalf("expected banned terms to retain default tokens")
+	}
+}
+
+func createPolicyTestFile(t *testing.T, path string) {
+	t.Helper()
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		t.Fatalf("mkdir %s: %v", path, err)
+	}
+	if err := os.WriteFile(path, []byte("demo"), 0o644); err != nil {
+		t.Fatalf("write file %s: %v", path, err)
+	}
+}