[Feature] Add per-kernel dispatch args dump for Insight Trace

[vegetabledoww]

Summary

Follow-up to PR #792: --dump-args currently only exports orchestrator-level arguments to tensor_dump/args_dump.json.

Downstream Insight Trace needs the actual per-dispatch kernel_entry(args) layout for individual incore kernels so it can replay a single kernel dispatch directly.

Motivation / Use Case

The current args_dump.json is useful for orchestration-level inspection, but it is not sufficient to reconstruct one real kernel dispatch such as QK / SF / PV / UP.

Insight Trace needs the finalized args after scheduler payload construction, including the real slot ordering and per-dispatch metadata. Without that, downstream tooling cannot reliably replay one incore kernel from dump artifacts.

Proposed API / Behavior

Add a separate kernel-level dump artifact, for example:

tensor_dump/kernel_args_dump.json

This new dump should:

• keep existing tensor_dump/args_dump.json unchanged for compatibility
• capture records after scheduler payload construction, using the actual kernel_entry(args) layout
• include per-dispatch identifiers such as:
  • dispatch_id
  • func_id
  • task_id
  • subtask_id
  • core_type
  • core_id
  • block_idx
• mark the capture stage as before_dispatch
• preserve the real arg_index ordering seen by the kernel
• include tensor arg metadata:
  • dtype
  • ndims
  • shape
  • pointer value if needed
• include scalar arg raw values with enough information to distinguish value/bits semantics
• include context pointer args separately from normal tensor/scalar args

A possible top-level schema would group args by dispatch and include:

• schema_version
• total_dispatches
• total_args
• dispatches[]

Alternatives Considered

• Reusing only args_dump.json: insufficient, because it reflects orchestration-level arguments rather than real per-kernel dispatch payload layout.
• Reconstructing dispatch args offline from existing dump artifacts: possible only heuristically, and too fragile for downstream replay tooling.

Additional Context

• Related baseline PR: Feature: Add unified tensor and args dump support #792
• PR URL: Feature: Add unified tensor and args dump support #792
• This issue tracks the functional gap left after Feature: Add unified tensor and args dump support #792: orchestrator-level args dump exists, but per-kernel dispatch args dump is still missing for Insight Trace replay.

[vegetabledoww]

Linked back to PR #792 for two-way tracking.