fix(stats): per-event aggregation so reprints add to Quick Stats instead of overwriting (#1378)

Statistics now aggregate over PrintLogEntry (one row per print event,
  the same table backing the global Print Log) rather than PrintArchive
  (one row per file). A reprint creates a new PrintLogEntry instead of
  overwriting the source archive's runtime fields, so:

  - a 100 g successful print + a 10 g failed reprint correctly sums to
    110 g / 2 prints / 1 successful / 1 failed in Quick Stats and the
    Prometheus /metrics endpoint (previously the failed reprint silently
    replaced the source archive's data; totals dropped from 100 g to 10 g)
  - the archive's card cost/energy_kwh are preserved on reprints (only
    the first run writes them); per-run actuals live on PrintLogEntry
  - failed/cancelled/stopped reprints record partial-aware filament: sum
    of tracked spool deltas when inventory is set up, else estimate
    scaled to progress%, else None — prevents the full slicer estimate
    from inflating totals on a print that stopped at 10 % progress

  PrintLogEntry gains six columns: archive_id (nullable FK, ON DELETE
  SET NULL so log entries survive archive deletion preserving #1343
  soft-delete-vs-stats decoupling), cost, energy_kwh, energy_cost,
  failure_reason, created_by_id. Idempotent SQLite + Postgres migrations.

  New per-archive surface:

  - archive list response carries run_count / last_run_at /
    total_filament_actual_grams / successful_run_count / failed_run_count
    via a single batch JOIN, no N+1
  - new GET /archives/{id}/runs endpoint returns every PrintLogEntry for
    the archive (ARCHIVES_READ permission, newest-first ordering)
  - archive cards render an orange "N prints" badge for archives with
    more than one run; clicking the badge opens a dedicated PrintLogModal
    with date/status/duration/filament/cost columns plus failure_reason
    under failed runs. Also reachable via the context menu's new "Print
    Log" entry (works for single-run archives too), and embedded at the
    top of the Edit Archive modal for context.

  The purge_stats=true delete path now hard-deletes linked PrintLogEntry
  rows up front so the archive's contribution truly leaves the totals;
  without it, ON DELETE SET NULL would orphan the runs and leave them
  counting toward stats.

README.md

@@ -127,6 +127,7 @@ Optional but recommended — drop the [`slicer-api/` Compose stack](slicer-api/R
 - Plate thumbnail browsing for multi-plate archives (hover to navigate between plates)
 - Archive comparison (side-by-side diff)
 - Tag management (rename/delete across all archives)
+- **Per-archive print history** — Each archive card shows an `N prints` badge whenever a model has been printed more than once (reprint + failed retries all counted). Click the badge for the full per-archive Print Log — every individual run with date, status, duration, filament used, cost, and failure reason. Reprints contribute new rows so a failed retry never overwrites the source archive's data — the original 100 g successful print stays visible alongside the 10 g failed reprint, and Quick Stats add up to 110 g across both events.
 - **Print Log** — Chronological table view of all print activity with columns for date/time, print name, printer, user, status, duration, and filament. Filterable by search, printer, user, status, and date range. Pagination with configurable page size. Clear button removes log entries without affecting archives.
 
 ### 📊 Monitoring & Control