Capture WordPress runtime state for generated-site Playground replay

## Problem
Studio Web Workflow Bench r38 now passes with durable artifact publication, but the generated-site Playground replay remains `partial` because WP Codebox only captures the starting blueprint plus read/write mount text files.

The public `blueprint.after.json` is reviewer-clickable, but it is not yet a faithful replay of the generated WordPress site. It contains only plugin activation and login steps, so Playground opens a runtime shell without the generated site state.

## Evidence
- Passing Workflow Bench report: https://homeboy-artifacts-tunnel.dev.chubes.net/homeboy/workflow-bench/runs/studio-web-data-machine-diagnostic-20260614-lab-merged-r38/report.md
- Source evidence: https://homeboy-artifacts-tunnel.dev.chubes.net/homeboy/workflow-bench/runs/studio-web-data-machine-diagnostic-20260614-lab-merged-r38/evidence.json
- Current partial blueprint: https://homeboy-artifacts-tunnel.dev.chubes.net/homeboy/workflow-bench/runs/studio-web-data-machine-diagnostic-20260614-lab-merged-r38/artifacts/plain-site-data-machine/studio-web/attempt-1/live-2026-06-14T15-43-49-973Z/plain-site-data-machine/studio-web/wp-codebox-artifacts/runtime-mqdyf9i0-qca8id/blueprint.after.json
- Replay notes: https://homeboy-artifacts-tunnel.dev.chubes.net/homeboy/workflow-bench/runs/studio-web-data-machine-diagnostic-20260614-lab-merged-r38/artifacts/plain-site-data-machine/studio-web/attempt-1/live-2026-06-14T15-43-49-973Z/plain-site-data-machine/studio-web/wp-codebox-artifacts/runtime-mqdyf9i0-qca8id/blueprint.after-notes.json
- Artifact manifest: https://homeboy-artifacts-tunnel.dev.chubes.net/homeboy/workflow-bench/runs/studio-web-data-machine-diagnostic-20260614-lab-merged-r38/artifacts/plain-site-data-machine/studio-web/attempt-1/live-2026-06-14T15-43-49-973Z/plain-site-data-machine/studio-web/wp-codebox-artifacts/runtime-mqdyf9i0-qca8id/manifest.json

The replay notes report:

```json
{
"replayStatus": "partial",
"capturedFileCount": 0,
"replayableFileCount": 0,
"limitations": [
"Text files from readwrite mounts are embedded in blueprint.after.json as writeFile steps; binary files are copied into artifacts but not replayed yet.",
"Database exports, option diffs, uploaded media, active theme/plugin state, and screenshots are not captured yet."
],
"nextCaptureTargets": [
"database-export",
"active-theme",
"active-plugins",
"uploads",
"binary-file-replay"
]
}
```

## Desired outcome
For successful generated-site runs, WP Codebox should capture enough WordPress runtime state to make `blueprint.after.json` a real generated-site replay instead of an activation/login-only shell.

The next useful target is a Playground blueprint that can recreate the generated WordPress site from public artifacts after the source runtime has been destroyed.

## Acceptance criteria
- Successful Studio Web generated-site recipe runs emit `replayStatus: "replayable"` when runtime state capture succeeds.
- `blueprint.after.json` includes the generated site's durable WordPress state, including database content/options needed to render the generated site.
- Active theme and active plugin state are represented in the replay artifact.
- Uploaded/media or binary state is either replayed from public artifacts or explicitly represented as a remaining structured limitation.
- The existing `files/runtime-evidence/replay-status.json` contract from #952 remains the single orchestration surface for status and reasons.
- A fresh Studio Web Workflow Bench run for `plain-site-data-machine` reports `Durable replay: replayable=1, partial=0, not-available=0`.

## Related
- #951 asked for reliable replay proof status and was closed by #952.
- #952 successfully added the replay summary surface that made this remaining capture gap explicit.

## AI assistance
- **AI assistance:** Yes
- **Tool(s):** OpenCode (GPT-5.5)
- **Used for:** Drafted this issue from r38 Workflow Bench evidence and WP Codebox replay-status artifacts.

Commencez par files/runtime-evidence/replay-status.json et inspectez les artefacts référencés blueprint.after.json, blueprint.after-notes.json et manifest.json issus d’une exécution de plain-site-data-machine. Utilisez le contrat replay-status existant comme limite d’orchestration et exécutez le Studio Web Workflow Bench après les modifications. C’est terminé lorsque le blueprint capture l’état durable de la base de données, des options, du thème, du plugin et des médias disponibles, signale les limitations structurées pour tout ce qui n’est pas rejoué et indique replayable=1, partial=0, not-available=0.

Rédigé par le modèle d'indexation à partir du texte de l'issue.