Function resolve_placeholders_in_op_params 

pub fn resolve_placeholders_in_op_params(
    op: &mut ParsedOp,
    kernel: &dyn Kernel,
) -> Result<(), String>

SRD-68 Push 5c — resolve {name} placeholders in a single op’s params against kernel. Used by validation wrappers at construction time to pre-resolve config like relevancy.k = "{k}" against their dispenser’s canonical kernel, so the downstream spec parsers see a literal value (10) rather than a surviving placeholder string.

Per-cycle binding LHS names pass through unchanged — the wrapper resolves those via wires at cycle time (e.g. relevancy.expected = "{ground_truth}" stays as-is so the wrapper can register it on the fixture’s pull plan and read it per cycle).

Single-op variant of the legacy bulk-mutation pass; the per-template granularity lets each wrapper resolve against its own dispenser’s canonical kernel rather than a shared activity-layer parent.