feat: flatten output into variants/ and intermediates/

Drop per-job subdirs for phone-friendly Syncthing layout with
stem-suffixed filenames; keep web state in meta/.

Co-authored-by: Cursor <cursoragent@cursor.com>

SOUL.md

@@ -60,7 +60,8 @@ bad venue wifi. Nobody signs up, nobody logs in. Whoever has the link
   (phone/folder setup is out of band).
 - No beamer/projector product built into this repo.
 - Not a DAM (digital asset manager) — no albums, tagging, search,
-  retention policies. `incoming/` and `jobs/` are the whole data model.
+  retention policies. `incoming/`, `variants/`, and `intermediates/`
+  are the whole data model.
 - No auto-deletion of incoming uploads. Ever. The worker only reads/copies.
 - No Syncthing container in this compose — Syncthing runs on the host.
 
@@ -70,8 +71,12 @@ bad venue wifi. Nobody signs up, nobody logs in. Whoever has the link
 - Data volume (Syncthing share): `${DATA_HOST_DIR}` — prod default
   `/home/frank/sync.schwenk.online/data/livef12`, local override `./data`.
   Bind-mounted into `worker` and `web` at `/data` (see `compose.yml`).
-- Layout under the share: `incoming/` (phone drop), `jobs/` (full tree
-  syncs back), `processed.json`.
+- Layout under the share:
+  - `incoming/` — phone drop
+  - `variants/` — `{stem}_original.jpg`, `{stem}_rembg.png`, `{stem}_vN.png`
+  - `intermediates/` — `{stem}_vN_*.png` (incl. `_post_0` …)
+  - `meta/` — web bookkeeping JSON (optional `.stignore` on phone)
+  - `processed.json`
 - Domain: `live.f12.rocks`, routed via the shared external `traefik`
   network, TLS via `myresolver` (see `INFRASTRUCTURE.md`).
 - rembg model cache lives in the named Docker volume `rembg_cache`, not
@@ -83,8 +88,8 @@ bad venue wifi. Nobody signs up, nobody logs in. Whoever has the link
 - Never delete or move files under incoming/ from worker code — Syncthing
   is the writer there. (reason: uploads are the one copy of the original
   that exists outside a phone's camera roll)
-- Keep every intermediate image in jobs/<id>/intermediates/ — don't clean
-  them up automatically. (reason: useful for debugging bad filter picks,
+- Keep every intermediate image under intermediates/ — don't clean them
+  up automatically. (reason: useful for debugging bad filter picks,
   disk is cheap compared to re-running gmic)
 - gmic/rembg subprocess calls always run under `nice` (see NICE_LEVEL) —
   the worker box needs to stay responsive for other things during an