fix(package): include pyproject.toml so an installed copy can bootstrap

scripts/bootstrap.py resolves --group against <repo-root>/pyproject.toml,
but package_plugin.py's INCLUDE tuple never shipped that file. An archive
built and unpacked elsewhere could never bootstrap (F1). Verify: built an
archive with package_plugin.py, unpacked it to a tmp dir, ran
scripts/bootstrap.py against the unpacked copy -- "bootstrap: guard 1.3.0"
/ "bootstrap: ok", exit 0. Also fixed two stale pyproject.toml comments
still naming the pre-port scripts/bootstrap.sh.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/package_plugin.py

@@ -51,6 +51,7 @@ INCLUDE = (
     "SECURITY.md",
     "LICENSE",
     "BUILD_STAMP",
+    "pyproject.toml",
 )
 REQUIRED = (".claude-plugin/plugin.json", "BUILD_STAMP")