feat(tensor): TensorId — structured identity from the module tree, assignTensorIds, describe() renderer (SKEEP-003 P1, S0.5)

[michalharakal]

Summary

SKEEP-003 slice S0.5 (milestone M0 #1001, PRD M0-F5; decisions #9/#10): TensorId — one stable, human-readable identity per tensor derived from the model structure — plus the describe() debugger renderer.

• sk.ainet.lang.tensor.TensorId(modulePath, parameter, discriminator?): structured, with canonical (model.layers.blk.3.attn.q_proj.weight, …scores#step=17), legacyPath() (the slash form bindPaths / the WeightNameResolvers use: MLP/blk.0/attn), parse(canonical), fromLegacyPath(path, parameter), withDiscriminator, view(range).
• Tensor.id: TensorId? default member (null = anonymous — a matMul b in a notebook stays free); TensorIdBearer { var id } implemented by VoidOpsTensor, OpsBoundTensor (delegates to its origin so ids survive re-binding to another context) and the context-factory origin tensor.
• ModuleNode.assignTensorIds(root = name): TensorIdAssignment — explicit, idempotent walk over the module tree: module-path segments are exactly bindPaths' segments (id.legacyPath() == node.path), parameter = short name ("<module>.weight" → weight); tensors that cannot carry an id are reported in notCarried, all are in the tensors map (ids["model.layers.blk.0.attn.weight"]). No runtime code path changes (M0-A5).
• Tensor.describe() / TensorStorage.describe(id) (sk.ainet.lang.memory, opt-in): TensorId · Format · Shape · storage kind · origin · scope · StorageId with — for the M1-only fields (scope, storage id); file-backed storage prints Mapped · <path> @0x<offset>.
• Tests: TensorIdTest, AssignTensorIdsTest (tree walk, bindPaths parity, idempotence, not-carried, re-binding), DescribeTest.
• BCV: lang-core jvm dump regenerated (additions only).

Activation ids (debug-only in eager, always-on when tracing) are the hook withDiscriminator is for; wiring them into tracing is P7. toString() is not overridden (existing tests and logs rely on current renderings); describe() is the renderer the IDE/debugger surface (decision #12) builds on.

Stacked on #1051 (S0.4 — Format); retarget to develop after it merges.

Test plan

Full local gate (scripts/pr-gate.sh, JDK 25) on the stacked tree; results in the first comment.

Closes #1010

🤖 Generated with Claude Code

[michalharakal]

Local gate scripts/pr-gate.sh (JDK 25) on e821ffb (stacked on #1051):

=== pr-gate: JVM tests ===                                      BUILD SUCCESSFUL in 4m 20s (run 1; run 2 up-to-date)
=== pr-gate: apiCheck ===                                       BUILD SUCCESSFUL (backend-cpu dump regenerated: inherited getId())
=== pr-gate: verifyNpmPins jsTest wasmJsTest wasmWasiTest ===   BUILD SUCCESSFUL in 2m 39s
=== pr-gate: linuxX64Test ===                                   BUILD SUCCESSFUL in 1m 29s
=== pr-gate: assemble ===                                       BUILD SUCCESSFUL in 2m 9s
=== pr-gate: :skainet-test:skainet-test-java:test ===           BUILD SUCCESSFUL in 21s
pr-gate: all legs passed.

Targeted: lang-core sk.ainet.lang.memory.*, TensorIdTest, sk.ainet.lang.nn.topology.* 23/23.

[michalharakal]

Rebased onto the updated base after #1053 merged into feature/1008-format-and-encoding (lang-core API dump regenerated; no source change). The chain is now: #1051 (Format + AllocationSpec) ← #1054 (TensorId) ← #1055 (NameMap) ← #1056 (MemoryPlan) ← #1057 (skainet-plan CLI); merging each into its base keeps the next one a single-commit diff.