test(cli): add init→upgrade→doctor parity test suite

[diberry]

Parent: #817 (FR-2, FR-3)

The Fix

Add tests that validate the init ↔ upgrade contract:

1. Parity test: programmatically compare what init creates vs what ENSURE_DIRECTORIES covers — fail if they differ
2. Workflow test: init → delete .squad/casting/ → upgrade → doctor passes
3. Parametric test: for each ENSURE dir, delete it, upgrade, verify recreated

Why

The casting directory was added to init but not upgrade because no test crossed both paths. This prevents future init/upgrade drift.

Acceptance Criteria

• Test: ENSURE_DIRECTORIES covers all directories init creates
• Test: upgrade on pre-casting repo → doctor all-green
• Test: parametric delete → upgrade → recreate for each dir
• CI runs these tests on PRs touching init/upgrade/doctor

Effort: 2-3 hrs