feat: Add PeerTube & PieFed auto-update, improve classifier

Add auto-update scripts and review examples for PeerTube and PieFed,
bringing total auto-updating services to three.

The classifier now includes the current and target version in the
prompt so it can correctly evaluate conditional upgrade notes like
"follow v8.1.0 instructions if upgrading from <= v8.0.2". Without
this context the model would conservatively flag patch releases as
manual.

All auto-update wrappers now use `bash -euo pipefail` when calling
remote scripts so failures in upstream deploy/upgrade scripts
propagate correctly instead of silently succeeding.

test_classifier.py now accepts a service name argument and derives
realistic version numbers from the release notes for testing.

services/piefed/review-examples/auto-3.txt

@@ -0,0 +1,35 @@
+action: auto
+reason: Major feature release with post relocation, video uploads, and realtime chat. No database migrations or manual admin action required.
+---
+### Big deals, omg
+
+ - Mods can move a post, with replies and votes, to another community. The change federates to other instances (except Lemmy, for now).
+ - Upload video files while creating a video post - no external host needed. Admin setting to limit who can do this (to save space).
+ - Realtime chat - conversation immediately updates on screen when a new PM arrives.
+
+### More good stuff
+
+ - Author-deleted posts are still visible to them and anyone with the url. No more loss of high-value comments with the OP deletes.
+ - Search filters - nsfw and minimum post score
+ - Improve speed of cross-posting form on mobile
+ - Emoji tokens like `:blush:` can be used in post or comment body. No GUI support yet.
+ - Admin setting to disable local copies of remote images - good for single-user instances
+ - Replying to a comment marks associated inbox item as read
+ - Updated HPT-Fruits theme
+ - 196 no longer excluded from default community import
+ - Remove unused community rating feature
+ - Remove unused instance vote weight feature
+ - Remove ineffective þ to 'th' replacement
+ - Improved accessibility - better contrast, fixed many incorrectly-used `aria-label`s
+ - Updated translations - Basque, Chinese, Japanese
+
+### API:
+ - Admins can ban/unban users through the API. piefed.world was maintaining custom code for this, hopefully it'll make their version upgrades faster.
+
+### Bugs fixed
+
+ - PMs
+ - Markdown parsing
+ - Speed up loading of profile pages for admin users 
+ - Friendica post parsing
+ - Passkeys login UX tweak