Implement JSONL export/import and shift to text-first architecture

This is a fundamental architectural shift from binary SQLite to JSONL as
the source of truth for git workflows.

## New Features

- `bd export --format=jsonl` - Export issues to JSON Lines format
- `bd import` - Import issues from JSONL (create new, update existing)
- `--skip-existing` flag for import to only create new issues

## Architecture Change

**Before:** Binary SQLite database committed to git
**After:** JSONL text files as source of truth, SQLite as ephemeral cache

Benefits:
- Git-friendly text format with clean diffs
- AI-resolvable merge conflicts (append-only is 95% conflict-free)
- Human-readable issue tracking in git
- No binary merge conflicts

## Documentation

- Updated README with JSONL-first workflow and git hooks
- Added TEXT_FORMATS.md analyzing JSONL vs CSV vs binary
- Updated GIT_WORKFLOW.md with historical context
- .gitignore now excludes *.db, includes .beads/*.jsonl

## Implementation Details

- Export sorts issues by ID for consistent diffs
- Import handles both creates and updates atomically
- Proper handling of pointer fields (EstimatedMinutes)
- All tests passing

## Breaking Changes

- Database files (*.db) should now be gitignored
- Use export/import workflow for git collaboration
- Git hooks recommended for automation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

cmd/bd/init.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/fatih/color"
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/beads/internal/storage/sqlite"
+)
+
+var initCmd = &cobra.Command{
+	Use:   "init",
+	Short: "Initialize bd in the current directory",
+	Long: `Initialize bd in the current directory by creating a .beads/ directory
+and database file. Optionally specify a custom issue prefix.`,
+	Run: func(cmd *cobra.Command, args []string) {
+		prefix, _ := cmd.Flags().GetString("prefix")
+		if prefix == "" {
+			// Auto-detect from directory name
+			cwd, err := os.Getwd()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error: failed to get current directory: %v\n", err)
+				os.Exit(1)
+			}
+			prefix = filepath.Base(cwd)
+		}
+
+		// Create .beads directory
+		beadsDir := ".beads"
+		if err := os.MkdirAll(beadsDir, 0755); err != nil {
+			fmt.Fprintf(os.Stderr, "Error: failed to create %s directory: %v\n", beadsDir, err)
+			os.Exit(1)
+		}
+
+		// Create database
+		dbPath := filepath.Join(beadsDir, prefix+".db")
+		store, err := sqlite.New(dbPath)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error: failed to create database: %v\n", err)
+			os.Exit(1)
+		}
+
+		// Set the issue prefix in config
+		ctx := context.Background()
+		if err := store.SetConfig(ctx, "issue_prefix", prefix); err != nil {
+			fmt.Fprintf(os.Stderr, "Error: failed to set issue prefix: %v\n", err)
+			store.Close()
+			os.Exit(1)
+		}
+
+		store.Close()
+
+		green := color.New(color.FgGreen).SprintFunc()
+		cyan := color.New(color.FgCyan).SprintFunc()
+
+		fmt.Printf("\n%s bd initialized successfully!\n\n", green("✓"))
+		fmt.Printf("  Database: %s\n", cyan(dbPath))
+		fmt.Printf("  Issue prefix: %s\n", cyan(prefix))
+		fmt.Printf("  Issues will be named: %s\n\n", cyan(prefix+"-1, "+prefix+"-2, ..."))
+		fmt.Printf("Run %s to get started.\n\n", cyan("bd quickstart"))
+	},
+}
+
+func init() {
+	initCmd.Flags().StringP("prefix", "p", "", "Issue prefix (default: current directory name)")
+	rootCmd.AddCommand(initCmd)
+}