logging: take the log policy from ecore

setupLogging's level parser, its os.Stderr.Stat colour probe and its three-key
mask list were one of six copies. Defaults(conf, section) resolves all of it now
and the handler stays here, which is the split that package documents.

Three things follow from taking the instance's list instead of this service's
own: the mask set gains the config-file private keys and the migration DSN that
siblings had already learned to redact, NO_COLOR is honoured, and verbosity can
be set for one run with $LOG_LEVEL or -d. [dolt.sr.ht]log-level is unchanged.

log: take the logrus bridge from auxilia

The bridge was written here because remotesrv.ServerArgs.Logger demands a
*logrus.Entry and nothing else, and letting it log around our handler meant
its records skipped the masks. None of that is specific to dolt or to
SourceHut, so it now lives in auxilia beside scribe, where the next library
that demands a logrus entry can reach it.

log: bridge dolt's remotesrv logger into slog

remotesrv takes a *logrus.Entry and nothing else, so passing nil left it
writing through logrus' standard logger: its own format, its own stream,
and no mask between a field named token and the journal. It is the half
of this process that serves clones and pushes — the likeliest place for
a credential to reach a log field, and the one that was logging around
everything the previous commit configured.

internal/logrusbridge hands it an entry whose only exit is a
logrus.Hook: output to io.Discard, a formatter that produces nothing,
and the logrus level left wide open so the slog handler does the
filtering from the one setting in config.ini. Fields cross as attributes
rather than a formatted blob, which is what lets a mask keyed on the
attribute path fire at all.

Verified against logrus v1.9.3 rather than assumed: Entry.log fires
hooks before it writes, before Logger.Exit and before the panic, so a
Fatal or Panic record reaches slog before the process ends. Both arms
are tested.

The package takes nothing from this service and belongs beside scribe in
auxilia; it is here because it was needed here first.

log: replace logrus with slog behind auxilia's scribe handler

Every logger field this service owned was a *logrus.Entry threaded
through a constructor, which is what logrus costs for want of a usable
default. They are slog.Default().With("component", ...) now, and the
threading is gone with them; the shared middleware's panic reports land
in the same handler, which is why the daemon sets the default before
anything that can fail.

The handler is scribe's tint handler: level from [dolt.sr.ht]log-level,
source positions, and masks keyed on the attribute path for the three
credentials this service handles — the unified-login cookie, the
Internal fernet token and the Authorization header the remotesapi reads
a PAT or a keypair JWT out of. Errors go through scribe.Err, so a culpa
error's hint reaches the operator on its own line.

logrus stays in go.mod: dolt's remotesrv.ServerArgs takes a
*logrus.Entry and nothing else. It is now confined to Config.DoltLogger,
which is the only place this service names it.

dolt-git-hook is deliberately untouched: what it writes to stderr is the
notice a pushing user reads through git, not a log.

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.

doltsrht: pass full os.Args to server.New so -b binds the web listener

getopt skips argv[0] as the program name, so os.Args[1:] made it swallow the
first real flag (-b) and silently fall back to defaultWebAddr (localhost),
leaving the web UI unreachable from Traefik. Match compare/upstream: pass os.Args.

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

cmd: doltsrht and doltsrht-migrate binaries, module tidy