Complete Ole2Frame: embed a picture file from a script

EmbedPicture builds the frame with OCS's own EmbeddedImage and
build_embedded_ole, so the opaque storage is never scripted. PNG, JPEG and
BMP are stored as read and other formats are re-encoded as PNG. The lifecycle
test now creates through Python; a new test covers formats, aspect, origin,
layer and refusals.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/plugin-host-model-completion-plan.md

@@ -7,9 +7,9 @@ Build a general Python document model over the OCS host API for all **43 canvas
 As of 20 September 2026, the working branch is `plugin/host-model-api` at
 `a8dd3640` plus the Leader increment, published as draft PR
 [#1391](https://github.com/HakanSeven12/OpenCADStudio/pull/1391). Host API is
-v7. The Python feature has explicit writes for **43 of 43** canvas kinds: 40
-are creatable (the legacy `Polyline`, `Ole2Frame` and `Body` are update-only). This is **not** 41 completed
-kinds: Tolerance, Shape, AttributeEntity, Hatch, MLine, Dimension, MultiLeader, Table, PolygonMesh, PolyfaceMesh, Mesh, Wipeout, Point, Line, Circle, Arc, Ellipse, LwPolyline, Spline, Text, MText, Ray, XLine, Solid, Face3D, Solid3D, Region and Surface pass every completion gate; Insert now passes every gate too; the audited Polyline (update-only by decision), Polyline2D and Polyline3D pass every gate that their format allows.
+v7. The Python feature has explicit writes for **43 of 43** canvas kinds: 41
+are creatable (the legacy `Polyline` and `Body` are update-only). This is **not** 41 completed
+kinds: Tolerance, Shape, AttributeEntity, Hatch, MLine, Dimension, MultiLeader, Table, PolygonMesh, PolyfaceMesh, Mesh, Wipeout, Point, Line, Circle, Arc, Ellipse, LwPolyline, Spline, Text, MText, Ray, XLine, Solid, Face3D, Solid3D, Region, Surface and Ole2Frame pass every completion gate; Insert now passes every gate too; the audited Polyline (update-only by decision), Polyline2D and Polyline3D pass every gate that their format allows.
 AttributeDefinition passes its host and real IPC lifecycle but remains short of
 `Complete` because the previously pinned CAD codec dropped optional ATTDEF
 fields during DXF reads; revalidate that blocker against the current
@@ -183,3 +183,4 @@ exact queue above and update statuses with evidence after each increment.
 - Timed booleans in a release build (details in [cadkernel-body-path.md](cadkernel-body-path.md)). A curved box-and-cylinder boolean takes about 1 to 2.2 s, overlapping spheres 0.2 s and planar operands 1 to 2 ms, against 23 s in a debug build. The kernel refuses many curved cases quickly with a reason (`Coincident`, `CutRefused`, `NoClosedForm`), including a second cut in an already drilled box. Recommendation: add a synchronous `SolidOperation::Boolean` that surfaces the refusal and leaves the operands untouched, test it with planar operands plus one ignored curved case, and note the 30 s per-script budget. No code changed in this step.
 - Implemented `SolidOperation::Boolean` and `doc.solids.union`, `subtract` and `intersect`, as recommended by the timing study. It runs synchronously, surfaces the kernel's refusal (`Coincident`, `CutRefused`, `NoClosedForm`) with a plain-language reason and the words "nothing was changed", consumes the operands unless `keep_operands`, and records one undo step. The lifecycle test uses planar boxes (millisecond cost, exact volumes, debug-safe) and an `#[ignore]` test documents a curved refusal. With this the kernel operations in the cadkernel note are all built. SectionSymbol is the only unmapped kind.
 - Mapped `SectionSymbol`, the last unmapped kind, so all 43 canvas kinds now have explicit writes. The blocker recorded earlier was overstated: cadcodec documents `points` as canonical, says the counts equal the point count in every verified export, and provides `sync_display_fields()`, which OCS's own edits already call; OCS also renders a symbol with no style or view link. The host derives the counts and projections when `points` changes and validates that references are existing `SectionViewStyle` and `ViewRep` class objects. Every gate passes except DXF, where cadcodec reopens a top-level `SECTIONLINE` as an unknown entity (issue 5 in the cadcodec write-up, pinned by a canary). Still unverifiable here: the meaning of `raw_flags_90` and AutoCAD's acceptance of a symbol with no parent view.
+- Completed `Ole2Frame` by adding creation. `SolidOperation::EmbedPicture` and `doc.embed_picture` build the frame from a picture file with OCS's own embedding code, so a script never touches the opaque storage; PNG, JPEG and BMP are stored byte-for-byte and other formats are re-encoded as PNG. The lifecycle test now creates through Python and the new creation-rules test covers formats, aspect, origin, layer and seven refusals. 30 kinds are complete.