feat: add zip file extraction support with error handling for invalid archives

README.md

@@ -58,6 +58,7 @@ devplacepy/
 | `/comments` | Comment creation, deletion |
 | `/projects` | Project listing, creation |
 | `/projects/{slug}/files` | Per-project filesystem: directory and file CRUD, upload, inline editing (public read, owner write) |
+| `/zips` | Zip job status (`/zips/{uid}`) and archive download (`/zips/{uid}/download`); archives are queued via `/projects/{slug}/zip` and `/projects/{slug}/files/zip` |
 | `/profile` | Profile view, editing |
 | `/messages` | Direct messaging |
 | `/notifications` | Notification list, mark read, live unread counts (`/notifications/counts`) |
@@ -203,6 +204,13 @@ and its full configuration are documented automatically - including future servi
 - **`NewsService`** - fetches news from `news.app.molodetz.nl/api`, grades with AI, stores articles >= threshold
 - **`BotsService`** - Playwright fleet of AI personas that browse and interact with a DevPlace instance, with live cost/usage metrics (opt-in; install the `bots` extra)
 - **`GatewayService`** - OpenAI-compatible LLM gateway at `/openai/v1/*`, forwarding to DeepSeek (default) with optional vision augmentation; the single point of truth for AI that every other service routes through (enabled by default)
+- **`JobService` / `ZipService`** - generic async job framework (`services/jobs/`) for heavy, blocking work run off the request path; `ZipService` is the first consumer, building project zip archives in a subprocess
+
+### Async job framework and zip downloads
+
+`services/jobs/` is the standard way to run blocking work asynchronously and hand the caller a result URL. A shared `jobs` table is the queue (discriminated by `kind`); `queue.enqueue()` inserts a `pending` row from any worker, the lock-owning worker processes jobs in `JobService.run_once` (reap, recover orphans, refill up to a concurrency limit, prune expired), and status is polled from the database. Retention is built in: each job service deletes its own expired artifacts via a `cleanup` hook (default 7 days, admin-configurable). To add a kind, subclass `JobService`, set `kind`, and implement `process()` and `cleanup()`.
+
+`ZipService` archives a project (or a file/folder subtree) into `{crc32}.{slug}.zip` using the standalone `zip_worker` subprocess, with a CRC32 over the output. The frontend `app.zipDownloader` (any `data-zip-download` element, plus the files context menu) enqueues, polls `/zips/{uid}`, and downloads from `/zips/{uid}/download`. The job uid is the capability token, so anyone with the link can download. CLI: `devplace zips prune` (delete expired) / `devplace zips clear` (delete all).
 
 ### Adding a service