License peo4c under GPL-3.0-or-later and ship third-party notices

- Add the GPL-3.0 LICENSE and SPDX headers to peo4c's own files.
- Add THIRD_PARTY_NOTICES.md listing every bundled component, its
  license and where its license text lives in the image, plus a
  trademark disclaimer; reference it from the README.
- Ship neo4j-browser's LICENSE, NOTICE.txt and LICENSES.txt with a
  source archive of the built commit, as the GPL requires.
- Ship Apache AGE's LICENSE and NOTICE, which the base image lacks.
- Collect license texts for Python packages whose wheels omit them,
  from PyPI sdists or vendored copies in docker/licenses/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker/collect-python-licenses.py

@@ -0,0 +1,84 @@
+# SPDX-FileCopyrightText: 2026 Bart Broere
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Make sure every Python distribution in an environment ships its license text.
+
+Most wheels include their license files in ``*.dist-info``. For the ones that
+do not, copy its license files to ``<output>/<name>-<version>/``, taking them
+from ``<vendored>/<name>/`` when present and otherwise from the source
+distribution on PyPI. Run with the interpreter of the environment to inspect:
+``/opt/pgadmin/bin/python collect-python-licenses.py <output> <vendored>``.
+"""
+
+import io
+import json
+import re
+import sys
+import tarfile
+import urllib.request
+import zipfile
+from importlib import metadata
+from pathlib import Path
+
+LICENSE_FILE = re.compile(r"(^|/)(LICEN[CS]E|COPYING|NOTICE|AUTHORS)[^/]*$", re.IGNORECASE)
+
+
+def has_license_file(dist):
+    return any(LICENSE_FILE.search(str(f)) for f in dist.files or [])
+
+
+def sdist_members(name, version):
+    with urllib.request.urlopen(f"https://pypi.org/pypi/{name}/{version}/json", timeout=60) as r:
+        urls = json.load(r)["urls"]
+    sdist = next((u for u in urls if u["packagetype"] == "sdist"), None)
+    if sdist is None:
+        return {}
+    with urllib.request.urlopen(sdist["url"], timeout=120) as r:
+        data = r.read()
+    found = {}
+    if sdist["filename"].endswith(".zip"):
+        with zipfile.ZipFile(io.BytesIO(data)) as z:
+            for n in z.namelist():
+                if n.count("/") == 1 and LICENSE_FILE.search(n):
+                    found[n.split("/", 1)[1]] = z.read(n)
+    else:
+        with tarfile.open(fileobj=io.BytesIO(data)) as t:
+            for m in t.getmembers():
+                if m.isfile() and m.name.count("/") == 1 and LICENSE_FILE.search(m.name):
+                    found[m.name.split("/", 1)[1]] = t.extractfile(m).read()
+    return found
+
+
+def vendored_files(vendored, name):
+    directory = vendored / name
+    if not directory.is_dir():
+        return {}
+    return {f.name: f.read_bytes() for f in directory.iterdir() if f.is_file()}
+
+
+def main(output, vendored):
+    output, vendored = Path(output), Path(vendored)
+    missing = []
+    for dist in sorted(metadata.distributions(), key=lambda d: d.metadata["Name"].lower()):
+        if has_license_file(dist):
+            continue
+        name, version = dist.metadata["Name"], dist.version
+        files = vendored_files(vendored, name)
+        if not files:
+            try:
+                files = sdist_members(name, version)
+            except Exception as e:  # noqa: BLE001 - report and carry on
+                print(f"{name} {version}: could not fetch sdist: {e}", file=sys.stderr)
+        if not files:
+            missing.append(f"{name} {version}")
+            continue
+        target = output / f"{name}-{version}"
+        target.mkdir(parents=True, exist_ok=True)
+        for filename, content in files.items():
+            (target / filename).write_bytes(content)
+        print(f"{name} {version}: added {', '.join(files)}")
+    for item in missing:
+        print(f"WARNING: no license file found for {item}", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main(sys.argv[1], sys.argv[2])