Render delivery attempt detail in the event log (closes #202)

Expanding a delivery on the event log page now shows each recorded
attempt: attempt number, outcome, status code, duration, error and
response body. Previously a failure rendered as "target: failed" and
diagnosing it meant opening the per-webhook SQLite file by hand.

The response body is cut by SQLite via substr over a blob cast, the
same projection the event body uses, so an oversized stored response
never becomes a Go string. The page reports the cut with a marker.

Response bodies and errors are remote content, so both go through a
new delivery.Redactor that strips the target's own destination URL,
path, query and userinfo, plus the values of credential-shaped
request headers, before rendering. A cut body goes through RedactCut
as well, which drops any tail that is a proper prefix of a secret:
the remote chooses the padding in front of a credential it echoes,
so it chooses where the cut falls inside that credential. Target
configuration keeps reaching the template only as a TargetView.

Redactors are built from an unscoped target load. Deleting a target
only soft deletes the row while its deliveries survive, and a scoped
load would leave exactly those deliveries rendering unredacted. The
views the page lists stay scoped.

Attempt loading is chunked so the IN clause cannot exceed SQLite's
bound-parameter limit, its error is reported rather than discarded,
and the page renders at most 20 attempts per delivery, counting what
it leaves out.

static/css/tailwind.css is regenerated with the repo's pinned
tailwindcss for the utility classes the new markup uses.

internal/handlers/export_test.go

@@ -19,6 +19,14 @@ func (s *Handlers) SetLogForTest(log *slog.Logger) {
 // to the handlers_test package.
 const MaxRenderedBodyBytesForTest = maxRenderedBodyBytes
 
+// MaxRenderedResponseBytesForTest exposes the event log's
+// delivery response cap to the handlers_test package.
+const MaxRenderedResponseBytesForTest = maxRenderedResponseBytes
+
+// MaxRenderedAttemptsForTest exposes the event log's
+// per-delivery attempt ceiling to the handlers_test package.
+const MaxRenderedAttemptsForTest = maxRenderedAttempts
+
 // DummyVerificationsForTest reports how many equivalent-cost
 // verifications were charged for usernames that do not exist. It
 // lets a test prove the anti-enumeration path ran without timing