fix: make maintainer tool output actionable

--emulator accepts a buildbot core name from a profile's cores:, and a
mistyped target gets the closest names instead of every target. diff_truth
shows destinations and reports unpaired entries as evidence, not removals.
The verify summary counts discrepancies, a shared destination names both
systems, a truth hash conflict names both cores, and pipeline steps carry
their place in the real run instead of N/8. Every GitHub API caller takes
the token from github_token(), which falls back to gh auth token.

scripts/generate_readme.py

@@ -22,6 +22,7 @@ sys.path.insert(0, os.path.dirname(__file__))
 from common import (
     compute_composition,
     count_catalog_matched,
+    github_token,
     list_registered_platforms,
     load_database,
     load_emulator_profiles,
@@ -286,7 +287,7 @@ def fetch_contributors() -> list[dict]:
 
     url = f"https://api.github.com/repos/{REPO}/contributors"
     headers = {"User-Agent": "retrobios-readme/1.0"}
-    token = os.environ.get("GITHUB_TOKEN", "")
+    token = github_token()
     if token:
         headers["Authorization"] = f"token {token}"
     try: