Replace synthetic placeholder with real Wikimedia Commons photo

src/test/resources/images/test-image.jpg is now a 960x720 JPEG (~104 KB)
copy of File:20200601_135745_Flowers_and_Bees.jpg from Wikimedia Commons
by Bernard Ladenthin (project copyright holder), captured on an Olympus
digital camera. EXIF copyright tag confirms authorship.

Licensing
- Commons page lists the photo under CC-BY-4.0.
- The same author additionally grants this file under the project's MIT
  license, so no runtime attribution machinery is needed.

Source bytes were fetched from a gist hosted on github.com (the only
host on the environment's network allowlist that the user could stage
the photo through after the earlier ladenthin.net and Wikimedia hits
both 403'd in this sandbox). The gist HTML page embeds the file content
as base64 in <td class="blob-code js-file-line"> cells; decoded to the
real bytes (sha256
19f0e2d7f19b6558900e6fdf2646fbebcc6051bbdb707d8ea569987fd7e84f92).

README in the same directory updated to describe provenance, license,
and override path. The synthetic placeholder commit message from
c6884ab still records the fallback design that produced the previous
file.

Author: claude

src/test/resources/images/README.md

@@ -2,37 +2,30 @@
 
 ## `test-image.jpg`
 
-A 256×256 JPEG used by `MultimodalIntegrationTest` to exercise the typed
-multimodal request path end-to-end without a network dependency.
+A 960×720 JPEG (~104 KB) used by `MultimodalIntegrationTest` to exercise
+the typed multimodal request path end-to-end without a network
+dependency.
 
-### Current contents
+### Provenance
 
-The currently-committed file is a **synthetic placeholder** generated by
-Pillow inside this repository (sky / field / sun / house shapes,
-~2.5 KB). It is a valid JFIF image with enough visual structure for
-`MultimodalIntegrationTest` to assert a non-empty reply from a small
-vision model.
-
-The intended replacement is the Wikimedia Commons photo
+This is a copy of the Wikimedia Commons photo
 [`File:20200601_135745_Flowers_and_Bees.jpg`](https://commons.wikimedia.org/wiki/File:20200601_135745_Flowers_and_Bees.jpg)
-by Bernard Ladenthin (project copyright holder), published on Commons
-under CC-BY-4.0 and additionally granted to this project under MIT by
-the same author. Drop a copy of that photo here as `test-image.jpg`
-(JPEG, any reasonable size — 640px wide is plenty) and commit the
-overwrite when convenient. The test will pick it up automatically.
+by Bernard Ladenthin (project copyright holder). Captured on an Olympus
+digital camera; the JPEG's EXIF copyright tag confirms authorship.
 
 ### License
 
-The synthetic placeholder contains no third-party content and is
-distributed under the project's MIT license together with the rest of
-the source tree. When swapped for the Wikimedia photo, the same MIT
-grant applies (per the author's note in the previous paragraph) — no
-attribution-banner machinery is needed at runtime.
+The Commons page lists the photo under CC-BY-4.0. The same author
+additionally grants this file for use in this project under the
+project's MIT license, so no runtime attribution machinery is needed.
+A `SPDX-FileCopyrightText: 2026 Bernard Ladenthin
+<bernard.ladenthin@gmail.com>` line in the commit that added this file
+records that grant.
 
 ### Override
 
-To point the test at a different file without overwriting this one, set
-the `net.ladenthin.llama.vision.image` system property on the `mvn test`
-command line. Any image the JRE can read works, provided the file
-extension matches one of `.png`, `.jpg`, `.jpeg`, `.webp`, `.gif` so
-`ContentPart.imageFile(Path)` resolves the MIME type.
+To point the test at a different image without overwriting this one,
+set the `net.ladenthin.llama.vision.image` system property on the
+`mvn test` command line. Any image the JRE can read works, provided the
+file extension matches one of `.png`, `.jpg`, `.jpeg`, `.webp`, `.gif`
+so `ContentPart.imageFile(Path)` resolves the MIME type.