feat(pdf): hand the annotation gesture policy to the viewer

CHANGELOG.md

@@ -22,6 +22,8 @@ The release run heads these entries with the version and opens a fresh
 
 - The rendered pdf view exposes `odr.annotation`: the five tools, live preview
   and undo, whose `getAnnotations()` produces exactly what `annotate` takes.
+  It marks on `mark()`, and `setOptions` holds the gesture policy: what marks,
+  which pointers draw, what a touch on an armed page does.
 
 - `PdfFile::is_annotatable` answers for the file what the `annotate` capability
   answers for the format, and narrows it. Encrypted and repaired pdfs say no.

docs/design/README.md

@@ -8,9 +8,6 @@
 - [The v7 public API](api-v7.md) — what the next major removes from
   `src/odr/*.hpp`, why, and in which pull requests: one road per operation, and
   the removals this document's *Open tasks* deferred until a major.
-- [PDF annotation design](pdf-annotation.md) — markup annotations (highlight,
-  freehand ink) written back as standard annotations via an incremental update:
-  why no PDF library, the JSON wire format, and the effort it costs.
 
 ## Diagrams