FIX-09: honest awaiting-timestamp disclosure at export

[ChelseaKR]

A packet with un-timestamped items previously exported silently, and only
verified as "NOT intact" when a recipient ran habitable verify. Surface the
state honestly at export instead (option (b) from the roadmap; no hard
--allow-incomplete gate, the export never fails).

• packet.py: build_packet computes awaiting = item_count - timestamped and,
  when > 0, _disclosures appends a plain-language note. This propagates
  automatically to bundle.json "disclosures", ExportResult.disclosures, the CLI
  print loop, and the app export result.
• disclosure.py: new localized awaiting_timestamp_note (EN/ES), following the
  privacy_originals_warning pattern. The copy is precise not to imply an
  awaiting item is worthless: its content hash still anchors it at capture; only
  the upper-bound date is missing.
• htmlpacket.py / pdf.py: read the awaiting count from the appendix and render
  the localized note in the packet's own disclosure section when awaiting > 0.
• tests: a mixed vault (one stamped, one deferred) asserts the note appears in
  ExportResult, bundle.json, and the packet HTML, and is absent when every item
  is timestamped.
• docs/ideation/02-large-scale-fixes.md: mark FIX-09 done.

Co-Authored-By: Claude Fable 5 noreply@anthropic.com

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Backfill PR for a completed roadmap item (roadmap/fix-09-honest-awaiting-timestamp-state-a, 1 commit(s) over main). Part of the portfolio roadmap batch.