web: rename a database from its settings page

A database's name lives in two places — the metadata row and the on-disk
store directory its path names — so a rename has to move both. The order
is creation's: the row first, where a name already taken is refused by the
unique index before anything on disk changes, then the store, then the
handle the remotesapi memoized under the old path. A store that will not
move rolls the row back, so the two halves never disagree about where a
database lives; only a failed rollback is escalated to a human, because
it is the one outcome no later request can repair.

storage.MoveStore is one os.Rename behind the containment guard DeleteStore
already used, extracted here as containedPath. It refuses an occupied
destination outright: os.Rename over an empty directory would succeed and
swallow it.

No redirect is left behind — the old address simply stops resolving, as on
git.sr.ht — so an existing clone needs its remote replaced, and a companion
of a git repository is re-provisioned under its old name by the next push
to that repository. The README's quickstart now says both.

web: answer what is ready across every tracker

web: mirror the git twin's description onto companion databases

The internal create endpoint accepts a description, but its only caller
— dolt-git-hook — never sends one: git.sr.ht's push context does not
carry it. Companion databases therefore all sat descriptionless on the
dashboard while their git twins had perfectly good descriptions.

Resolve the description server-side instead: a GitDescriber dependency
(internal GraphQL query to git.sr.ht in the owner's name, the same
network-key trust the hook uses to reach us, pointed the other way) is
consulted on every /internal/repos call. A fresh companion is created
with the twin's description; for an existing one the push doubles as the
sync point — a changed, non-empty git description overwrites the stored
one. An empty git description never clobbers one set in dolt's own
settings, and every failure mode (no twin, git.sr.ht down, no resolver
wired) degrades to no mirroring. The lookup is capped at 3s so the
hook's own 5s POST timeout is never exceeded.

Adds testify as a direct dependency for the new tests.

rename module to sourcecraft.dev/bigbes/sr-ht-dolt; depend on sourcecraft sr-ht-core

web: router, handlers, and sourcehut chrome

Chi route table per plan, SourceHut chrome port (nav/layout from
core.sr.ht Bootstrap structure), dual-flow clone box, dolt-key
association page with hash-fragment prefill, same-origin CSRF checks.
Handlers depend on small injected interfaces (StoreManager, RepoStore,
BrowseOpener, UserResolver) with production adapters included.