Add select-search userscript and bookmarklet

Makes any <select> with many options searchable, for web apps whose
dropdowns have no search. The original <select> stays in the DOM and
remains the source of truth: choosing an option sets selectedIndex and
fires native input/change events, so the host application and its form
submission are unaffected.

Handles option lists that the app repopulates at runtime via a per-select
MutationObserver, and new selects appearing after AJAX via a document-level
one. Filtering is substring-based, accent-insensitive and multi-token.

Built into both a Tampermonkey userscript and a bookmarklet from one source.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

build.sh

@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+# Bouwt het userscript en de bookmarklet uit src/select-search.js.
+# Gebruik: ./build.sh   (de bookmarklet belandt ook meteen in het klembord)
+set -euo pipefail
+
+here="$(cd "$(dirname "$0")" && pwd)"
+src="$here/src/select-search.js"
+hdr="$here/src/userscript-header.txt"
+dist="$here/dist"
+
+for f in "$src" "$hdr"; do
+  if [ ! -f "$f" ]; then
+    echo "build.sh: ontbrekend bestand: $f" >&2
+    exit 1
+  fi
+done
+
+if ! command -v python3 >/dev/null 2>&1; then
+  echo "build.sh: python3 is nodig om de bookmarklet te encoderen" >&2
+  exit 1
+fi
+
+if grep -q 'MATCH_PLACEHOLDER' "$hdr"; then
+  echo "build.sh: vul eerst de echte @match-URL in $hdr in" >&2
+  exit 1
+fi
+
+mkdir -p "$dist"
+
+# 1. Userscript = metadatablok + ongewijzigde core.
+cat "$hdr" "$src" > "$dist/select-search.user.js"
+
+# 2. Bookmarklet = core, URL-encoded achter javascript:.
+python3 - "$src" "$dist/bookmarklet.txt" <<'PY'
+import io, sys, urllib.parse
+
+src, out = sys.argv[1], sys.argv[2]
+code = io.open(src, encoding='utf-8').read()
+# Regelcommentaar sneuvelt zodra alles op een regel staat; strip het weg.
+lines = []
+for line in code.split('\n'):
+    stripped = line.strip()
+    if stripped.startswith('//'):
+        continue
+    lines.append(line)
+code = '\n'.join(lines)
+
+# Een bladwijzerbeheerder mag de nieuwe regels weggooien zonder dat de
+# bookmarklet stukgaat: dus geen enkel regelcommentaar meer overhouden.
+for n, line in enumerate(code.split('\n'), 1):
+    if '//' in line:
+        sys.exit('build.sh: regelcommentaar op regel %d breekt de bookmarklet: %s'
+                 % (n, line.strip()))
+
+url = 'javascript:' + urllib.parse.quote(code, safe="!#$&'()*+,-./:;=?@_~")
+io.open(out, 'w', encoding='utf-8').write(url)
+print('bookmarklet: %d tekens' % len(url))
+PY
+
+if command -v pbcopy >/dev/null 2>&1; then
+  pbcopy < "$dist/bookmarklet.txt"
+  echo "bookmarklet gekopieerd naar het klembord"
+fi
+
+echo "geschreven: $dist/select-search.user.js"
+echo "geschreven: $dist/bookmarklet.txt"