refactor(tools): bin/{subject}/{method} layout; Go serve+watch modules

Move serve/ (module) -> bin/server, tools/ -> bin/tools, replace bin/kb-watch
bash with bin/watch Go package; self-executing Go shebangs bin/serve.go and
bin/kb/watch.go; Docker + CI + git/import + docs repointed. Multi-stage image
builds static serve+watch binaries (no Go runtime in container).

bin/web/search

@@ -25,7 +25,7 @@ import urllib.parse
 import urllib.request
 from pathlib import Path
 
-TOOLS = Path(__file__).resolve().parents[1].parent / "tools"
+TOOLS = Path(__file__).resolve().parents[1] / "tools"
 sys.path.insert(0, str(TOOLS))
 sys.path.insert(0, str(TOOLS / "web-search"))