nixpkgs: Refresh channels and inputs

Rebase the fork branches and refresh nixpkgs, home-manager, and the
approved ancillary inputs. Update kernel and release metadata, adapt
removed package and Home Assistant options, and keep Determinate Nix
on its tested nixpkgs revision to avoid duplicate Boost patches.

Retire Sharry and its public endpoint because copyparty replaces it.
Document the GitHub mirror gate and require real devshell and system
builds in the upgrade validation workflow.

docs/sites/colony/shill/containers/object.md

@@ -1,7 +1,6 @@
 # object
 
-Object storage and the Nix binary cache, plus a few small self-hosted web apps (Sharry,
-HedgeDoc, wastebin).
+Object storage and the Nix binary cache, plus HedgeDoc and wastebin.
 
 - **Source:** [`shill/containers/object.nix`](../../../../../nixos/boxes/colony/vms/shill/containers/object.nix)
 - **Host:** NixOS container on [`shill`](../README.md) (bind-mounts `/mnt/minio` and
@@ -14,7 +13,6 @@ HedgeDoc, wastebin).
 | --- | --- | --- |
 | MinIO | `9000` (S3) / `9001` (console) | S3-compatible object storage, `s3.nul.ie` + `*.s3.nul.ie` (virtual-host style via `MINIO_DOMAIN`), console at `minio.nul.ie`; region `eu-central-1`; data on the `/mnt/minio` XFS volume |
 | Harmonia | `5000` | Nix binary cache at `nix-cache.nul.ie` — `harmonia-dev` cache serves `shill`'s `/nix/store` out of a dedicated store view rooted at `/var/lib/harmonia` (bind-mounted from `/mnt/nix-cache`), signed with the `nix-cache.key` secret; a `harmonia` user with authorized keys exists for cache pushes |
-| Sharry | `9090` | file sharing at `share.nul.ie`; Postgres on [colony-psql](colony-psql.md), files stored in the `share` MinIO bucket; fixed `dev` account + invite signup; mail via `mail.nul.ie`; configured share-size limit |
 | HedgeDoc | `3000` | collaborative markdown notes at `md.nul.ie`; Postgres on [colony-psql](colony-psql.md); anonymous edits but no anonymous notes, email login, no open email registration |
 | wastebin | `8088` | pastebin at `pb.nul.ie` |
 | atticd | `8069` | **currently disabled** (`services.atticd.enable = false`) — an alternative Nix cache that would store locally and sit behind `nix-cache.nul.ie`; config (including the `object/atticd.env` secret) is kept around |
@@ -29,10 +27,10 @@ See the consolidated [network assignments](../../../../networking.md#box-assignm
 
 ## Backing services
 
-- [colony-psql](colony-psql.md) — Sharry and HedgeDoc databases (atticd too, when enabled).
+- [colony-psql](colony-psql.md) — HedgeDoc's database (atticd too, when enabled).
 - MinIO buckets back other boxes' services: Gitea LFS/packages (with the `middleman` MIME hack
   for Docker manifests), Mastodon's `mastodon` bucket and the Bluesky PDS `pds` bucket on
-  [toot](toot.md), and Sharry's `share` bucket.
+  [toot](toot.md).
 
 ## Notable config files