raw derive PDF: Kopf nennt Bildseiten (images) und nicht zugeordnete Seiten (unmatched); neue Anweisung read-page-images für den gezielten Blick auf diese Seiten, Schwelle 20 Seiten (#234); 10.1.0-beta.7

Files changed:
- CHANGES.md
- VERSION
- docs/how-to/ingest-a-source.md
- docs/reference/commands/raw-material-and-uploads.md
- instructions/ingest-large-tree.md
- instructions/read-page-images.md
- instructions/wiki-ingest/SKILL.md
- raw/CONTRACT.md
- tools/CONTRACT.md
- tools/chemenu/commands/raw/derive.py
- tools/chemenu/filters/pdf.py
- tools/chemenu/filters/pdf_layout.py
- tools/chemenu/tests/test_raw_derive_binary.py
- types/source.guidance.md

Co-Authored-By: Claude Code <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

types/source.guidance.md

@@ -34,6 +34,7 @@ knowledge). One source page stands for **one logical source**, which may span se
 - Summarize the key claims in the summary section
 - Put anything actionable in the action items section
 - Put deliberate omissions in the not-extracted section - see below
+- Put what was read from a page image in a section of its own - see Page images below
 - Link the entities and concepts mentioned under related entities/concepts
 
 ## Not Extracted
@@ -51,6 +52,27 @@ source is renegotiated on every later pass.
 - Belongs on the source page, not in `kb/log.md`: it is a statement about *this* source, and the
   log is chronological rather than per-source.
 
+## Page images
+
+What a model read from a page image of `original.pdf` (`instructions/read-page-images.md`) is not
+text the tool derived, and it is not the source's own wording: it is a reading. It gets its own
+section on the source page, headed in the KB language (a German instance: `Am Seitenbild gelesen`),
+so a reader can tell it from the summary.
+
+- **One entry per statement, with the page.** Each entry names the page number and says that it was
+  read from the page image, so it is checked against that page and not against `derived.md`.
+- **Name the intermediary.** Where a subagent did the reading, the entry says so; the provenance
+  chain then has its middle party visible (`instructions/capture-session.md` calls that
+  second-hand).
+- **Cite it as the original.** Another page that takes over a statement from this section cites it
+  with `cite add --file original.pdf`; text taken from the derivation is cited with
+  `--file derived.md`. The two files are one source with two readings, and the qualifier is what
+  tells them apart.
+- **Hedge as the reading deserves** (`kb/CONVENTIONS.md` § Hedging): a label that could not be read
+  with certainty is written as uncertain, not completed.
+- **Pages not read stay visible.** A selected page nobody looked at, with the reason, goes into the
+  not-extracted section.
+
 ---
 
 Relevant Notes: