refactor: restructure API, deduplicate code, expand test coverage

- Extract shared DeferClose helper, removing 14 duplicate copies
- Rename PlayWright-prefixed types to cleaner names (BrowserOptions,
  BrowserSelection, NewBrowser, etc.)
- Rename fields: ServerAddress, RequireServer (was DontLaunchOnConnectFailure)
- Extract shared initBrowser/mergeOptions into browser_init.go,
  deduplicating ~120 lines between NewBrowser and NewInteractiveBrowser
- Remove unused locator field from document struct
- Add tests for all previously untested packages (archive, aislegopher,
  wegmans, useragents, powerball) and expand existing test suites
- Add MIGRATION.md documenting all breaking API changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cmd/browser/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"io"
 	"os"
 
 	"github.com/urfave/cli/v3"
@@ -12,9 +11,6 @@ import (
 	"gitea.stevedudenhoeffer.com/steve/go-extractor/cmd/browser/pkg/browser"
 )
 
-func deferClose(cl io.Closer) {
-	_ = cl.Close()
-}
 func main() {
 	cmd := &cli.Command{
 		Name:  "browser",
@@ -31,7 +27,7 @@ func main() {
 				return err
 			}
 
-			defer deferClose(b)
+			defer extractor.DeferClose(b)
 
 			// now open the user specified url
 			doc, err := b.Open(ctx, target, extractor.OpenPageOptions{})
@@ -39,7 +35,7 @@ func main() {
 				return err
 			}
 
-			defer deferClose(doc)
+			defer extractor.DeferClose(doc)
 
 			article, err := extractor.Readability(ctx, doc)