Delete or repopulate empty projects/policyengine-api-full directory

Summary

projects/policyengine-api-full/ on origin/main contains only uv.lock — no source, no pyproject.toml, no package directory. The tree is effectively abandoned.

What goes wrong

$ git ls-tree -r --name-only origin/main -- projects/policyengine-api-full
projects/policyengine-api-full/uv.lock

A lone uv.lock with no pyproject.toml or package content:

• Pins dependencies nothing can consume, so it drifts out of sync with reality on every uv bump without anyone noticing.
• Confuses readers — the directory name suggests a "full" sibling of policyengine-api-simulation, but there's nothing there.
• Breaks workspace-wide commands (pyright, ruff, pytest) that try to discover projects via directory structure.

Related: #271 (pyright broken on full API) implicitly references this tree but frames the problem around type-checking rather than emptiness.

Suggested fix

Pick one:

1. Delete the directory if the full API has moved to policyengine-api-v2-alpha (which appears to be the active direction based on #83 "Simulation/Report V2 Migration Foundation"). Most honest option — close #271 as no-longer-applicable.
2. Repopulate with a real pyproject.toml + package if the intent was to keep the non-simulation endpoints alive in this monorepo. Revisit #271 after.

A note in the top-level README explaining the monorepo layout (simulation lives here, full API lives elsewhere) would also reduce confusion for new contributors.

Severity

Low / tech-debt — doesn't break anything, but decays over time and confuses contributors.

Relates to

#271 (pyright on full API).

Inspect the origin/main tree at projects/policyengine-api-full/ and compare the related context in issue #271 and the references to policyengine-api-v2-alpha and policyengine-api-simulation. Determine whether deletion or repopulation is intended, then verify that workspace discovery and the top-level README no longer describe a misleading project; done means the directory layout and related issue references are consistent.