Closes one of docs/product.md's open product decisions ("whether
repositories must be cached for offline browsing"), at the human product
owner's explicit request.
A new file-backed RepositoryListCache persists the ALL/no-organization-
filter repository list after every successful load, using a dedicated
plain DTO (not the domain RepositorySummary directly, since
RepositoryCoordinates/RepositoryRef validate through a private-constructor
factory Gson's reflection would otherwise bypass). RepositoryListViewModel
falls back to it whenever a live fetch of that view fails with a
network-classified error (cold start or mid-session), seeding
repositorySnapshots so pagination keeps working from the cache. A
page-level banner makes the fallback impossible to mistake for a live
view. The cache is cleared on logout.
Deliberately scoped to just the landing list -- not favorites,
organization filters, or repository internals (branches/files/history) --
confirmed with the human product owner after they live-tested the
fallback via airplane mode and asked about extending it further; decided
to hold that off.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
