TICKET-047: Issue #101 'alloc.__main__ zero coverage' is stale — consolidate tests #113

Summary

Issue #101 claims alloc/__main__.py has zero test coverage. This is no
longer true: __main__ is exercised by two test classes, and a third
was added this cycle. The issue should be closed and the duplicate coverage
consolidated.

Evidence

• tests/test_cli.py::TestMainModule (line ~803) — 2 tests (import, has main).
• tests/test_actor_critic.py::TestMainModule (line ~505, tagged TICKET-034)
  — 7 tests (import, delegation, callable, exit code, invalid args, AST
  guard check, runpy invocation).
• tests/test_portfolio.py::TestMainEntryPoint (added this cycle) — 2 tests
  (delegation identity, exit-code propagation).
• All pass: pytest tests/test_cli.py::TestMainModule tests/test_actor_critic.py::TestMainModule tests/test_portfolio.py::TestMainEntryPoint
  → 11 passed.

Impact

• Issue TICKET: Add test for alloc.__main__ module entry point #101 is misleading; a newcomer would believe the entry point is
  untested and may add redundant tests.
• Three near-duplicate TestMainModule/TestMainEntryPoint classes scatter
  the same concerns across three files.

Suggestion (implementation plan)

1. Close issue TICKET: Add test for alloc.__main__ module entry point #101 with a note that coverage now exists (cite the three
   classes).
2. Consolidate the __main__ tests into a single tests/test_main.py
   (or keep them in test_cli.py since __main__ delegates to cli.main),
   removing the duplicates in test_actor_critic.py and
   test_portfolio.py.
3. Keep the strongest assertions: delegation identity
   (alloc.__main__.main is alloc.cli.main), exit-code propagation, and the
   runpy python -m alloc --help invocation.

Acceptance criteria

• Issue TICKET: Add test for alloc.__main__ module entry point #101 closed.
• A single canonical test location for alloc.__main__.
• No loss of the delegation / exit-code / runpy assertions.