3d09174c16
Closes H4 and the remaining formatter half of H2. - New @shared/format.ts is the single home for fmtBytes/fmtSpeed/fmtEta, imported by both main and renderer. main/lib/formatters.ts re-exports them. - DownloadProgress now carries raw speedBytesPerSec/etaSeconds instead of pre-formatted speed/eta strings. main's parseProgress emits the raw numbers. - The renderer stores the raw numbers on DownloadItem; QueueItem formats them for per-item display, and summarizeQueue sums/maxes them directly. The lossy string->number->string round-trip in queueStats (parseSpeed / parseEtaSeconds / a local formatSpeed / formatEta) is deleted, along with a duplicate fmtEta in store/downloads.ts. - Per-item and aggregate speed now use the same 1024-based scale; the aggregate previously used a 1000-based formatter (a latent inconsistency). Tests updated for the raw-number contract (parseProgress, summarizeQueue). typecheck + 248 tests + eslint + prettier green. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>