feat(dr_egeria_folder): subfolders, exclude and per-file run-as user; manual

[dwolfson]

Why

dr_egeria_folder promises the same _batch.json semantics as the Egeria Portal's folder loader (egeria-workspaces bootstrap_batches.py). The Portal now recurses into subfolders and sets a run-as user per file (odpi/egeria-workspaces#618), so the CLI needs the same rules to keep a folder running the same way from either.

It also fixes a silent regression. Object-form files entries ({"file": …, "userid": …}) never matched the old string comparison, so a folder using them fell back to alphabetical order.

What changes

commands/cat/dr_egeria_folder.py:

• Subfolders run in place. A files entry can be a file, "sub/x.md" or "sub/". Unlisted files, then unlisted subfolders, follow alphabetically and are reported as ordering warnings; so are stale entries.
• New exclude field. README.md and output/plumbing folders (dr-egeria-outbox, logs, data, …) are skipped. The outbox folders hold processed copies with live commands.
• Run-as user. userid is set per folder (inherited by subfolders) or per entry; the nearest declaration wins. Passwords come from EGERIA_BOOTSTRAP_PASSWORD_<USERID>, else --user_pass. The command uses one client per user for the run. --no-manifest-userids runs everything as --userid.
• A file reachable twice runs once.

docs/dr_egeria_manual.md: new sections on dr_egeria_folder, the _batch.json manifest, and the Portal's automatic loading; it also documents --user_pass.

Testing

• Same results as the Portal: order and run-as users match the live Portal's /api/bootstrap/batches for every Coco batch. When the CLI runs the Data Hub folder on its own, it runs data-field-naming/ inline at the README's step 6, as intended; in the Portal that subfolder is its own batch.
• Per-user sign-in works: dr_egeria_folder "coco-workbooks/6. data-privacy" --validate signed in as faithbroker, as its manifest says, and validated 106 commands with 0 failures.
• Not run: a --process run.