feat(slicer): Pipelines — archive entry point + slicer progress toast (#1425 PR B follow-up)

Two real gaps from the PR B drop:

1. Run-with-pipeline only existed in the file manager. Operators who keep
   working files in archives had to copy them to the library to use a
   pipeline.

2. Triggering a slice via a pipeline produced a silent multi-second-to-
   minute wait. The manual SliceModal flow shows the sticky
   "Slicing X - Generating G-code 75%" persistent toast; the pipeline
   path went through asyncio.create_task directly and never registered
   with SliceJobTracker.

Archive entry point
- POST /slicer-pipelines/{id}/check-eligibility and /run accept
  source_archive_id as an alternative to source_library_file_id (XOR,
  enforced by Pydantic validator).
- PipelineRun.source_archive_id is a new nullable FK column with the
  ALTER TABLE migration in run_migrations (idempotent via _safe_execute,
  works on SQLite + Postgres).
- _resolve_source branches: archive path reads source_3mf_path with
  fallback to file_path, mirroring routes/archives.py.
- ArchiveCard's context menu picks up a "Run with pipeline" item next to
  Slice (only on source archives), gated on useSlicerApi + pipelines:run.
  Slice (only on source archives), gated on useSlicerApi + pipelines:run.
- Path-safety: SEC-PATH-OK markers added at both LibraryFile.file_path
  and archive.source_3mf_path join sites, citing the upload-time
  validators.

Progress toast
- Pipeline orchestration is now the `run` callable of a
  slice_dispatch.enqueue call — the same dispatcher SliceModal uses —
  instead of a bare asyncio.create_task. The SliceJob lifecycle drives
  the existing progress toast end to end with no separate notification
  surface for pipeline runs.
- PipelineRun.slice_job_id is set before the 202 returns.
- RunWithPipelineModal calls useSliceJobTracker().trackJob() from
  runMutation.onSuccess.
- RunWithPipelineModal source prop is now {kind, id, filename}
  mirroring SliceModal.SliceSource; api.checkPipelineEligibility +
  api.runPipeline take a discriminated-union source argument.

frontend/scripts/check-i18n-parity.mjs

@@ -219,7 +219,7 @@ const IT_COGNATES = [
   'Bambu Cloud', 'Orca Cloud',  // brand names — same in every locale
   'AMS Filament Backup',  // Bambu Lab product/firmware feature name
   'Email',  // common loanword in Italian, used verbatim in UI labels
-  'Pipeline',  // #1425 — Slicer Pipelines (cognate in IT)
+  'Pipeline', 'slicing',  // #1425 — Slicer Pipelines (cognate in IT)
   'Status', 'Tag', 'Tags', 'Online', 'Offline', 'Standard', 'Filament',
   'Filaments', 'Software', 'Hardware', 'Stop', 'Reset', 'Test', 'Code',
   'Token', 'Server', 'Port', 'Plate', 'Layer', 'Modal', 'Pin', 'Pro', 'Mini',