chore: scaffold payroll extension

Repo tooling and LNbits extension metadata only — no runtime code yet, so
this lands separately from the feature work per the workspace commit rules
(cross-cutting concerns commit first).

- MIT licence, .gitignore, README
- Makefile + pyproject wired for the standard aio fork lint pipeline
  (black + ruff + mypy) and pytest
- config.json declaring id/version/tile so the extension is installable
  from the aiolabs catalog once there is something to install

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018jy52j9GRZ6XKa1Zt21LLj

README.md

@@ -0,0 +1,42 @@
+# Payroll
+
+Scheduled recurring payouts between LNbits wallets, driven by the instance
+**super user**.
+
+Pick a user from the account directory, point the payout at one of their
+wallets, set an amount + currency, a start date, how often it pays and how
+many times — Payroll then moves the money on schedule, from a source wallet
+you control, and keeps a ledger of every attempt.
+
+## Status
+
+Early. Built for `aiolabs` LNbits instances; see `docs/` for the data model
+and operational notes.
+
+## Who can use it
+
+Everything under `/payroll/api/v1/` that reads the account directory or
+touches a contract is gated on `check_super_user` — payroll moves money
+between accounts the operator does not own, so wallet-level admin keys are
+deliberately *not* enough. (`require_admin_key` authorises writes to your
+own wallet only; it is not instance-admin. See the auth table in the
+workspace `CLAUDE.md`.)
+
+Add `payroll` to `LNBITS_ADMIN_EXTENSIONS` so the extension is hidden from
+ordinary users in the UI as well.
+
+## Development
+
+```
+make          # black + ruff + mypy
+make test     # pytest
+```
+
+The dev LNbits compose mounts `~/dev/shared/extensions/` at `/shared` with
+`LNBITS_EXTENSIONS_PATH=/shared`, so this checkout *is* the installed
+extension. FakeWallet is enough — no regtest needed for anything except
+end-to-end Lightning behaviour.
+
+## Licence
+
+MIT