refactor: split opencode runtime and tests

pilot/README-webhook.md

@@ -463,15 +463,15 @@ for permanence.
 ## The opencode review engine
 
 The review "brain" runs on **opencode** (the AI coding-agent CLI), not a single
-cramped model call. `pilot/opencode_review.py` is the glue:
+cramped model call. `pilot/review/opencode.py` is the compatibility seam:
 
-1. `fetch_archive` — `GET .../archive/{sha}.tar.gz`, untar into a temp workdir
+1. `opencode_workspace.fetch_archive` — `GET .../archive/{sha}.tar.gz`, untar into a temp workdir
    (stripping the top dir) so the agent has the real files, not just the diff.
-2. `write_brief` — renders `.pragent/brief.md` (title, body, diff, repo
+2. `opencode_workspace.write_brief` — renders `.pragent/brief.md` (title, body, diff, repo
    `.pr-review.json`, prior reviews, sha, anchor hint).
-3. `drop_factory` — copies `opencode.json` + `.opencode/` (agents/skills/commands)
+3. `opencode_workspace.drop_factory` — copies `opencode.json` + `.opencode/` (agents/skills/commands)
    into the workdir as the project config.
-4. `run_opencode` — `opencode run --pure --format json --agent pragent
+4. `opencode.run_opencode` — `opencode run --pure --format json --agent pragent
    --dir <workdir> --model headroom/glm-5.2:cloud` headlessly. `--format json`
    emits NDJSON events: `parse_opencode_events` reconstructs the assistant text
    from `text` events and sums tokens/cost/steps from every `step_finish` event.
@@ -514,7 +514,7 @@ opencode run --pure --agent pragent --dir <checkout> --model headroom/glm-5.2:cl
   "$(python3 -c 'import sys;sys.path.insert(0,"pilot");import opencode_review as o;print(o._PROMPT)')"
 ```
 
-### Gotchas baked into `opencode_review.py`
+### Gotchas baked into the opencode review modules
 
 - **stdin=DEVNULL** — opencode blocks on stdin (permission prompt) when run
   headlessly via subprocess; closing stdin is required or it hangs to timeout.
@@ -603,4 +603,3 @@ webhook service went live.
 - Gitea 1.26.1: system webhooks broken (see above) → user-level webhooks instead;
   hook delivery-history API (`.../hooks/{id}/tasks`) returns 404, so delivery is
   observed via the pragent-webhook pod logs (`kubectl -n pragent logs -f deploy/pragent-webhook`).
-