feat(write-skill): GED attach op — upload the source document onto its invoice (erp#43)

document-attach.sh uploads a source piece (the supplier's own PDF) onto an
invoice's GED via POST /documents/upload — idempotent by (object, filename,
sha256): before any POST the object's GED is listed and a same-named entry is
downloaded back and sha256-compared. Identical → deduped no-op; different
content → ABORT (refuse-never-repair, overwriteifexists always 0, never
Dolibarr's overwrite flag). Read-back after upload: re-list + download +
sha256-verify. Module-relative download paths are derived from the listing's
fullname (supplier invoices carry an id-derived get_exdir prefix like
9/2/FAF2026013/…, so reconstruction would be wrong).

Promote integration: new `attach` op in promote-plan/promote-apply (OP_SCRIPT),
object_id resolvable via @ref and #supplierinvoice lookups; a relative `file`
resolves against the manifest's directory (replay packs carry pdfs/ beside the
manifest, gitignored — README documents the books@ re-fetch message ids).
promote-plan prints each file's sha256 (or a loud MISSING) at review time.
CLI: `arcodange sandbox attach`.

Proof: offline case 12 in tests/run-tests.sh (upload body, dedupe, conflict
abort, field refusal, manifest-relative resolution via stubbed /documents);
live: manifest-C-ged-attach.json applied twice on the sandbox — run 1 four
created, run 2 four deduped, one GED file per FAF2026010-013, stored sha256s
equal to the re-fetched sources; tests/replay-idempotency.sh extended with an
attach op (4 created → 4 deduped, ged_files count unchanged) and a live
same-name/different-bytes abort verified.

Closes erp#43

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01VRShc4QhLLU73FLHx9vskh

.gitignore

@@ -8,4 +8,8 @@
 secrets/
 *.key
 .claude/skills/**/.env
+
+# Replay-pack source PDFs — evidence, re-fetchable from books@ (email-ingest),
+# never committed (see each pack's README for the re-fetch recipe)
+.claude/skills/dolibarr-sandbox-write/replay-packs/**/pdfs/
 .claude/skills/**/examples/document_*.bin