bench(learn): harvest signals for the decision engine (decision-engine task 5)

`ousast plane harvest` (plane/harvest.py) writes two Runs over a label snapshot:
verify a/b + agree on the verify-family units (both sides of each labelled pair as
an opaque files-only Workspace, candidates outside the hunt's root, no declared
sites; v1 and dev-php pins with repo-facts first) and model roles on the candidate
files (pair excerpts grouped, one Task per population pin). Budgets sum under the
ceiling by construction. New roles task template; the generator re-pins it.

Spent by attribution: verify $2.54 (1961 calls, 150 units, 182 hunts per pass),
roles $1.40 (1034 calls, 799 files, 0 unclassified chunks); DeepSeek balance
19.63 -> 18.23. Engine on the pair corpus (benchmarks/learn/engine_pairs.py,
frozen e6ed785, one 3g container) is PARTIAL: 384 of 686 sides at commit, still
running; unfinished sides stay missing. benchmarks/learn/build_features.py built
1712 static+plane records into the memory store; counts-only record under
benchmarks/measurements/2026-10-01-decision-engine-harvest/.

source/roles parts are `none`, not `failed`, for a language without a declaration
pattern (C). ops/ax/README: Substrate golden-actor disk leak and the inline
Workspace limit (~20 KB).

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

ops/ax/README.md

@@ -41,6 +41,13 @@ afterwards (`go clean -cache -modcache`); rerunning the full Substrate install o
   only; the gateway dials the address the actor connected to, so the receiver is a Service dialled by ClusterIP
   with its name as Host. The Envoy gateway needs a Rust build; the agentgateway variant needs none.
 - Apply a Task after the Workspaces it binds; ax copies them at create time.
+- Every Task is its own actor template with a golden actor (~24 MB under `/var/lib/ate/actors` on the node). Deleting
+  them failed while the snapshot bucket ax's templates name (`dberkov-gke-dev3`, from `AX_SNAPSHOTS_BUCKET`) did not
+  exist in rustfs: golden actors piled up in `DELETING` and filled the disk during a 600-task harvest (2026-10-01).
+  Create that bucket in rustfs (an aws-cli pod with the `rustfs-bucket-init` env); even then a deleted actor's
+  directory stays on the node, so long Runs need a janitor that removes directories no live actor owns.
+- A Workspace's `files` reach the actor inline in one environment variable: above ~20 KB of content the template
+  fails with "actor template not found" (an 86 KB and a 31 KB excerpt did; 7 KB ran).
 
 ## Moving to a separate Kubernetes cluster (planned)