[claude] Let test fixtures use the normal CreateProject/OpenProject paths with in-memory sqlite

[myieye]

[Claude, autonomous]

LcmCrdt.Tests fixtures (MiniLcmApiFixture, DataModelSnapshotTests, several inline setups) hand-roll project init (SetupProjectContextForNewDb + InitProjectDb) because CreateProject opens and closes its own DbContext, which would drop the shared-cache in-memory DB. The copied init has already drifted from the real path once (the extra "trigger data migrations" step).

Fix:

• Hold one keep-alive SqliteConnection to the named in-memory DB (file:x?mode=memory&cache=shared) for the fixture's lifetime — the DB survives while any connection stays open, so CreateProject's open/close no longer wipes it. (Today this mostly works by accident via connection pooling.)
• Add an optional DbPath to CreateProjectRequest, used verbatim, so it can target the URI instead of computing {Path}/{code}.sqlite. Everything downstream already handles URIs.

Then fixtures run the real CreateProject/OpenCrdtProject init (migrations, ProjectData seeding, data migrations), and the initializedNewDb hack in LcmCrdtTestsKernel likely drops out.

Keep the Debugger.IsAttached real-file trick. SnapshotAtCommitServiceFileBasedTests stays file-based on purpose.