merge: P6, the evidence pipeline (branch P6, checkpoint ce366408)

The last of the paused branches, from its "not for merge" checkpoint:
extraction in ledger-import (text, pages, page images; capped, caught),
journaled as attachment.text_extracted; dedup by hash with
books.find_attachment and books.consolidate_duplicates; annotations and
books.set_entry_settles; the company record categories; the two fuzz
targets; feature attachment_text. Nineteen files conflicted with the
four P4b merges, resolved as plan 8.0.2 says: P6 retakes schema 18 (it
had taken 16, which S4.3 holds; S5 holds 17); the tool table is 129 and
the destructive count 31; both sides' appends kept with their seams
restored; one B-27 paragraph naming every feature; in the old-books
fixture P6's hand-written reimbursement is entry 7 (its ids collided
with S4.3's invoice); the replay fuzzer's list gains S7's
invoice.written_off; S4.3's issued-PDF test expects the extraction
record P6 journals right after a filing.

One integration defect between S7 and P6, found by the arap property
test and fixed here: under P6's dedup, a write-off whose evidence bytes
were filed already (the same collection letter for a second write-off of
the same invoice) was refused only after its entry had been journaled,
at the final link to the invoice ("already linked"). The write-off now
resolves the dedup before anything is journaled and keeps a link the
record already has to the invoice instead of refusing it; an explicit
existing_attachment_id already on an entry is still refused (S7's
one-receipt-once rule). P6's gate never ran before the pause; it runs on
main after this merge, and its ledger-store -> ledger-import dependency
is the open review point (plan 8.0.1).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

docs/verification.md

@@ -876,3 +876,17 @@ each harness's whole run, its compile of about 50 s included):
 | `bounds_kept_is_the_definition_on_books_in_bounds` | 34 | prove | (as above) |
 | `settle_is_exact` | 36 | prove | 1 |
 | `kani_symbolic_copy_canary` | (the checker: "Trusting the checker") | prove | 3 |
+
+
+## P6: the evidence pipeline
+
+No kernel arithmetic, `Ledger` command in the formal sense, or Lean step
+changed (P6 moves no money): `just prove` is unchanged and stays green.
+The new `Ledger` methods (`annotate_attachment`, `set_entry_settles`) are
+replay-side records with validation only, covered by
+`annotations_replay_and_project` and `reimbursed_is_derived_from_settles_only`;
+the arithmetic-shaped work (the extraction caps and the page scale) is in
+`ledger-import`, outside the kernel, and is tested and fuzzed rather than
+proved. The formal bar for the next unit that touches these paths is
+unchanged; the P12 paragraph in `docs/testing.md` lists the mutation
+targets.