breadclip: document pin verb, config file, and ignore rules

- EVENTS.md: `bread.command.clip.pin` and `bread.clip.pinned` /
  `.pin.failed` are now implemented; `select` stays explicitly not
  implemented with the reason. AGENTS.md follows.
- README: Configuration section, Ctrl+P bind, updated privacy notes
  (CLIPBOARD_STATE + ignore rules), JPEG image entries, primary badge.
- check.yml also runs on pushes to `main` — a push to main triggers a
  dev-track release build, so it should be linted/tested first.
- release.yml uses `${GITHUB_REPOSITORY}` instead of a hard-coded
  `Breadway/breadclip` for the GitHub mirror release upload.

.forgejo/workflows/check.yml

@@ -1,10 +1,11 @@
 name: check
 
-# Fast-fail lint/test on short-lived work branches, before it ever reaches
-# main and triggers a dev-track release build.
+# Fast-fail lint/test on short-lived work branches, and on `main` itself —
+# a push to main immediately triggers a dev-track release build, so it
+# should be linted/tested first, not shipped unchecked.
 on:
   push:
-    branches: ['feature/**', 'fix/**']
+    branches: ['feature/**', 'fix/**', 'main']
 
 jobs:
   check: