Design notes §4 makes the dashboard surface load-bearing — with no
default DL handler, users wouldn't know dead letters exist
otherwise.
New route: `apps/[slug]/dead-letters/+page.svelte` — list view
columns per the design notes:
- `created_at`, `source`, `op`, `script_id`, `attempt_count`,
`first/last_attempt_at`, `last_error` (truncated; clickable)
- per-row Replay + Mark resolved buttons
- expandable row detail panel showing full payload (JSON) +
full last_error
- unresolved-only filter (default on); refresh button
Per-app detail page (`apps/[slug]/+page.svelte`) grows a "Dead
letters" link in the tabs nav, with a red unresolved-count pill
when > 0. Loaded in parallel with the existing app loaders so it
doesn't slow the page.
Apps list (`apps/+page.svelte`) shows the same red pill next to
each app's name when its unresolved count > 0. Counts fetched in
parallel after the apps list lands; failures here are non-fatal
(just no badge).
API client wiring: `api.deadLetters.{count,list,get,replay,resolve}`
mirrors the v1.1.1 admin endpoints. `DeadLetterRow` type added to
the dashboard's API shape declarations.
dashboard's svelte-check passes (369 files, 0 errors, 0 warnings).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>