Import the MetaMesh app family from Worph/AppStore

23 apps (MetaCore, the library/network/client tiers and 13 MetaFeeder*)
move out of the general-purpose Worph/AppStore into their own store so the
MetaMesh family releases on its own cadence.

- asset URLs repointed to cdn.jsdelivr.net/gh/Worph/MetaAppStore@main
- store scaffolding added (category/recommend/featured lists, licence,
  contributing, gitattributes)
- psd-source/meta-icons-v2 icon generator follows the apps

MetaMCP stays in Worph/AppStore: it is third-party metatool-ai software,
not part of MetaMesh.

Apps/MetaFeederUsenet/rationale.md

@@ -0,0 +1,64 @@
+# MetaFeeder · Usenet — Rationale
+
+## What deviation / exception is being requested
+
+1. `metafeederusenet-feeder` runs `user: 0:0`.
+2. The **NNTmux web UI is published on its own hostname**
+   (`metafeederusenetnntmux-<user>.<domain>`) with no AppShield sidecar in front of it — it
+   is protected by NNTmux's own login only.
+3. The seeded `nntmux.env` contains TMDB and TVDB API keys as literals.
+
+## Why it is necessary
+
+1. The feeder publishes resolved records to the shared MetaCore and writes plugin artwork
+   through its WebDAV endpoint; those targets are created and owned by MetaCore's
+   root-running container.
+2. NNTmux is a Laravel application with its own user table, session handling and admin
+   role. Its admin account is created at install from `$APP_DEFAULT_PASSWORD`, so
+   authentication is **enabled by default** — the "app's own built-in auth" alternative the
+   security checklist accepts. Fronting it with AppShield as well would double-prompt on
+   every page and breaks its own OTP and password-reset flows.
+3. Those two keys are NNTmux's upstream project defaults, shipped in its own
+   `.env.example`. They are shared read-only application keys for public metadata catalogs,
+   not user credentials, and they are what makes the app work immediately after
+   installation with no manual configuration. An operator can replace them from the NNTmux
+   admin UI.
+
+## Security mitigations in place
+
+- The NNTmux admin password is `$APP_DEFAULT_PASSWORD` — the platform-generated secret —
+  and the database password comes from the same variable. Neither is a hardcoded literal,
+  and both are surfaced to the user in `tips.before_install`.
+- The feeder's own configuration UI *is* behind AppShield + Authelia SSO
+  (`ghcr.io/yundera/appshield:2.0.9`).
+- `metafeederusenet-db`, `-redis` and `-manticore` are on the app-private
+  `metafeederusenet` bridge network, carry no Caddy labels and publish no host port, so no
+  sibling app on the shared `pcs` network can resolve or dial them.
+- NNTP provider credentials are deliberately left **blank** in the seed; the user fills
+  them in per `tips.before_install`. Nothing ships with a working news account.
+- The `nntmux.env` seed is guarded by `[ ! -f … ]`, so a reinstall or version upgrade never
+  overwrites the operator's provider settings. `scanner.sh` is intentionally rewritten on
+  every run — it is shipped code, not operator config, so a store update must be able to
+  replace a stale copy; the write is idempotent.
+- No user directories are mounted. All binds are under `/DATA/AppData/metafeederusenet/`,
+  declared in `x-compose-app.folders`.
+- `cpu_shares` on all nine services; every image pinned (the NNTmux and Manticore images by
+  digest).
+
+## Alternatives considered and rejected
+
+- **AppShield in front of NNTmux.** Two independent login gates on one UI; its OTP,
+  password-reset and API endpoints break behind the OIDC redirect.
+- **Blank the TMDB/TVDB keys.** The app then installs into a state where covers and
+  metadata silently fail until the user finds two upstream registration flows — a direct
+  violation of "works immediately after installation, no manual configuration required for
+  basic functionality".
+- **Run the feeder as `$PUID:$PGID`.** Writes into MetaCore's root-owned tree fail.
+
+## Data protection
+
+All state — MariaDB, the NZB store, the feeder cursor, the TMDB cache — is under
+`/DATA/AppData/metafeederusenet/`, the unit Maison archives on uninstall and restores from
+backup, so an uninstall/reinstall with "keep user data" comes back with the release
+catalogue intact rather than re-scanning Usenet from scratch. No user media directory is
+mounted into any service.