thumbnails.location in config.json can now name one folder for every
source's previews: <folder>/<source key>/<rel>_thumb<ext>. A source key is
a readable slug plus a short hash of the source's identity, stored in the
folder's marker (.promptmanager-thumbnails.json) with the install that
made it. Serving, on-demand and capture writes, listings, clear, delete,
duplicates, the temp sweep and History covers all follow it; a leftover in
<source>/thumbnails is never served and other text under thumbnails/ is
refused.
A missing, unplugged or foreign folder is unavailable (a probe checks it
every 5 s within 2 s; a stalled or failing store call flips it at once):
originals are served, nothing is written anywhere, the folder is never
re-created, and generate, convert and clear answer 409
location-unavailable. A bad config value is unavailable too, never a
fall-back to the sources.
No UI yet: POST /settings refuses thumbnail_location (409
location-needs-move); GET /settings reports it with its path, the
thumbnail status without one. Sources inside or around the folder and a
library move into it are refused.
A planned target keeps the plan's own containment rule (inside the
store, as the thumbnail job writes it); captures keep the serve rule.
The structural test also covers PREVIEW_FOLDER joins and the
repo-root modules; the write-lock test asserts the lock instead of
waiting on a timer; new tests cover nested roots in the after-scan
queue and a legacy upper-case preview served through the resolver.
Add py/api/preview_store.py: the store of a source, a preview's path,
URL parts to disk, containment (owns), a write generation and the lock
around every preview's final rename. Every preview reader, writer and
remover now asks it instead of joining <source>/thumbnails by hand:
serve, on-demand, capture (its path resolved when the write starts),
the after-scan queue, the thumbnail plans and job payloads, clear, the
temp sweep, History covers, the auto-tag listing and the owned-preview
lookups.
Source mode only: every path is the one built before, so nothing
changes on disk or on the wire. A structural test keeps new
thumbnails joins out of the backend.
Vito Sansevero