render: Job enum in the tables, single-loop match resolve, real CacheJob

M0a of the render-pipeline plan (docs/zh/plans/render-pipeline-threads.md):

- oak-node: every payload push site (58 across footage.rs, plugin.rs
  and the nodes/* effects) now boxes the Job enum instead of the raw
  payload. The enum gains CacheJob with a CacheJobPayload (path +
  time + fallback value, the C++ cachejob.h shape), plus safe as_*
  accessors and unsafe probe helpers beside job_ref.
- oak-render: RenderEvalHooks::resolve is one loop over the table —
  a single get_checked::<Job> probe per texture value, a match
  dispatch to process_footage/shader/plugin/color_transform/cache,
  and recursive resolution of the job boxes embedded in a payload's
  inputs (depth-capped, cycle-guarded) — replacing the four
  sequential full-table scans (resolve_*_jobs, deleted).
- The disk frame cache is real: frameio.rs implements a minimal
  self-describing F32 container (magic/version/dims/format/timestamp
  + payload, tmp-write + atomic rename, full header validation on
  load) because the OIIO bridge is a stub and EXR is unavailable in
  this build; process_cache_job genuinely reads the file before
  falling back to the job's (already resolved) fallback value.
- Tests: CacheJob roundtrip (save -> resolve -> pixel equality),
  missing-file fallback, nested cache-job-through-shader resolution,
  plus four frameio container tests. 2330 passed, 0 failed across
  the workspace.

crates/oak-node/src/nodes/displaytransform.rs

@@ -384,7 +384,7 @@ mod tests {
 			panic!("job row expected");
 		};
 		assert!(unsafe {
-			crate::handle::get_checked::<crate::jobs::ColorTransformJobPayload>(handle)
+			crate::jobs::color_transform_job(handle)
 		}
 		.is_some());
 	}