v2 restructure: Go client, Docker engine, release tooling

- Remove v1 Python CLI (src/kb_search/, tests/, root pyproject.toml, uv.lock, .venv)
- Add Go client with cross-platform build (client/)
- Add FastAPI engine with NVIDIA and multi-stage ROCm Dockerfiles (engine/)
- Add VERSION files for client and engine, wired into builds
- Add release.sh for automated build, tag, release, and Docker push
- Update README with build/release docs and ROCm migration note
- Clean up .gitignore for v2 project structure

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/cmd/add.go

@@ -0,0 +1,192 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/kb-search/kb/internal/api"
+	"github.com/kb-search/kb/internal/output"
+	"github.com/spf13/cobra"
+)
+
+var supportedExts = map[string]bool{
+	".pdf":  true,
+	".docx": true,
+	".html": true,
+	".md":   true,
+	".txt":  true,
+	".py":   true,
+	".sh":   true,
+	".go":   true,
+}
+
+var addCmd = &cobra.Command{
+	Use:   "add <path>",
+	Short: "Add a document or directory to the knowledge base",
+	Args:  cobra.MaximumNArgs(1),
+	RunE:  runAdd,
+}
+
+func init() {
+	addCmd.Flags().String("tags", "", "tags (comma-separated)")
+	addCmd.Flags().String("type", "", "document type")
+	addCmd.Flags().BoolP("recursive", "r", false, "recursively add directory contents")
+	addCmd.Flags().String("note", "", "add a text note instead of a file")
+	addCmd.Flags().String("title", "", "title for the note")
+	rootCmd.AddCommand(addCmd)
+}
+
+func runAdd(cmd *cobra.Command, args []string) error {
+	tags, _ := cmd.Flags().GetString("tags")
+	docType, _ := cmd.Flags().GetString("type")
+	recursive, _ := cmd.Flags().GetBool("recursive")
+	note, _ := cmd.Flags().GetString("note")
+	title, _ := cmd.Flags().GetString("title")
+
+	client := api.NewClient()
+
+	// Note mode
+	if note != "" {
+		fields := map[string]string{
+			"note": note,
+		}
+		if title != "" {
+			fields["title"] = title
+		}
+		if tags != "" {
+			fields["tags"] = tags
+		}
+		if docType != "" {
+			fields["type"] = docType
+		}
+
+		resp, err := client.PostMultipart("/api/v1/jobs", fields, nil)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		if err := api.CheckError(resp); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+
+		var result interface{}
+		if err := api.DecodeJSON(resp, &result); err != nil {
+			return fmt.Errorf("failed to decode response: %w", err)
+		}
+
+		if output.IsJSON() {
+			output.PrintJSON(result)
+		} else {
+			fmt.Println("Queued: note")
+		}
+		return nil
+	}
+
+	if len(args) == 0 {
+		return fmt.Errorf("path argument is required (or use --note)")
+	}
+
+	path := args[0]
+	info, err := os.Stat(path)
+	if err != nil {
+		return fmt.Errorf("cannot access %s: %w", path, err)
+	}
+
+	if !info.IsDir() {
+		// Single file upload
+		result, err := uploadFile(client, path, tags, docType)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+
+		if output.IsJSON() {
+			output.PrintJSON([]interface{}{result})
+		} else {
+			fmt.Printf("Queued: %s\n", filepath.Base(path))
+		}
+		return nil
+	}
+
+	// Directory upload
+	var files []string
+	walkFn := func(p string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			if !recursive && p != path {
+				return filepath.SkipDir
+			}
+			return nil
+		}
+		ext := strings.ToLower(filepath.Ext(p))
+		if supportedExts[ext] {
+			files = append(files, p)
+		}
+		return nil
+	}
+
+	if err := filepath.WalkDir(path, walkFn); err != nil {
+		return fmt.Errorf("failed to walk directory: %w", err)
+	}
+
+	var results []interface{}
+	for _, f := range files {
+		result, err := uploadFile(client, f, tags, docType)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error uploading %s: %v\n", f, err)
+			continue
+		}
+		results = append(results, result)
+		if !output.IsJSON() {
+			fmt.Printf("Queued: %s\n", filepath.Base(f))
+		}
+	}
+
+	if output.IsJSON() {
+		output.PrintJSON(results)
+	} else {
+		fmt.Printf("Queued: %d files\n", len(results))
+	}
+	return nil
+}
+
+func uploadFile(client *api.Client, path, tags, docType string) (interface{}, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("cannot open %s: %w", path, err)
+	}
+	defer f.Close()
+
+	fields := make(map[string]string)
+	if tags != "" {
+		fields["tags"] = tags
+	}
+	if docType != "" {
+		fields["type"] = docType
+	}
+
+	upload := &api.FileUpload{
+		FieldName: "file",
+		FileName:  filepath.Base(path),
+		Reader:    f,
+	}
+
+	resp, err := client.PostMultipart("/api/v1/jobs", fields, upload)
+	if err != nil {
+		return nil, err
+	}
+	if err := api.CheckError(resp); err != nil {
+		return nil, err
+	}
+
+	var result interface{}
+	if err := api.DecodeJSON(resp, &result); err != nil {
+		return nil, fmt.Errorf("failed to decode response: %w", err)
+	}
+	return result, nil
+}