[Lane 2 · kotlin-core] NotImplemented stubs — IRPA files larger than 2 GiB (multi-window mmap) #1422

Sub-issue of #1414 ([Feature]: Close the remaining NotImplemented stubs outside the operator surface).

Lane: 2 · Kotlin core
Skill needed: Kotlin JVM/Android; memory-mapped files.
Size: s (a few hours)
Blocked by: nothing

What to do

1. FileBackedTransfer on JVM and Android maps a single window and fails above 2 GiB (see Design: externalize weights via IREE parameter archive (supersedes #519) #523).
2. Map the file in ≤ 2 GiB windows and route reads to the right window; add a test with a sparse > 2 GiB file if the CI disk allows, otherwise a window-boundary unit test.
3. Run ./gradlew :skainet-io:skainet-io-iree-params:jvmTest.

Acceptance

• Reads that straddle a window boundary return the right bytes
• Result reported back on the parent issue

Notes

If something here turns out to be wrong or much bigger than the size label, comment on this issue or open a specific bug instead of blocking the parent.

Coverage matrix: docs/modules/ROOT/pages/reference/ops-status-matrix.adoc · How lanes work: Issue taxonomy