refactor(sdk-android): publish under io.github.priyanshujain.sanderling + ci docs fix (#27)

* refactor(sdk-android): publish under io.github.priyanshujain.sanderling

Move the published Maven coordinates to a sanderling sub-namespace so the
brand is visible in the dependency line (was io.github.priyanshujain:sdk-android).
Sub-namespace is auto-allowed by Sonatype under the verified parent groupId.

* chore: update sdk-android coordinates in folio + docs

Follow the groupId change to io.github.priyanshujain.sanderling:sdk-android.

* ci(docs): use --version flag for d2 install script

The d2 installer accepts --version vX.Y.Z, not --tag. The --tag form
was rejected as "unrecognized flag" on the docs workflow run after
PR #26 merged.

.github/workflows/docs.yml

@@ -28,7 +28,7 @@ jobs:
         run: sudo apt-get update && sudo apt-get install -y pandoc
 
       - name: Install d2
-        run: curl -fsSL https://d2lang.com/install.sh | sh -s -- --tag v0.7.1
+        run: curl -fsSL https://d2lang.com/install.sh | sh -s -- --version v0.7.1
 
       - name: Build site
         run: make docs