Add ignorance reduction plan for Java SDK native runtime embedding (#1917)

Create structured plan with 14 questions covering Maven module structure,
JNA binding design, callback threading, platform detection, binary
extraction/caching, transport integration, E2E testing, and CI workflows.
All resolution sections empty for human expert fill-in.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 4be81fa3-9a8c-4837-acd2-fce73c0e4277

Author: edburns