[Lane 2 · kotlin-core] NotImplemented stubs — SlicedTensorView.set for rank > 4 #1416

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

Lane: 2 · Kotlin core
Skill needed: Kotlin. Small, local change.
Size: s (a few hours)
Blocked by: nothing

What to do

1. set in skainet-lang/skainet-lang-core/src/commonMain/kotlin/sk/ainet/lang/tensor/SlicedTensorView.kt is hard-coded for 1–4 indices and throws above that.
2. Replace the when on index count with a loop that maps view indices to parent indices for any rank (the getter's logic is the reference).
3. Add a rank-5 test; run ./gradlew :skainet-lang:skainet-lang-core:jvmTest.

Acceptance

• Writes through a rank-5 view land in the right parent element
• 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