Add branch-cleanup task, fix taplo-lint pre-commit hook

- mise-tasks/branch-cleanup: delete merged local/remote branches via
  git + Forgejo API (1Password/env/flag token resolution)
- mise.toml: add uv (runs PEP 723 task scripts) and bat (ai-docs output)
- CLAUDE.md: re-point at AGENTS.md
- prek.toml: drop taplo-lint hook. It fetches the remote SchemaStore
  catalog, which the pinned (dormant) taplo CLI can no longer decode and
  which fails in sandboxed CI. check-toml still validates syntax and
  taplo-format still formats.
- .forgejo workflows / .gitea/template / dagger: minor resync

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

prek.toml

@@ -60,13 +60,15 @@ rev = "v3.12.0-2"
 hooks = [{ id = "shfmt", args = ["-i", "2", "-ci", "-bn"] }]
 
 # TOML - taplo
+# Only the formatter is enabled. taplo-lint is intentionally omitted: it fetches
+# the remote SchemaStore catalog on every run, which requires network access
+# (breaking sandboxed CI) and is broken in the pinned taplo CLI ("data did not
+# match any variant of untagged enum SchemaCatalog"). TOML syntax is already
+# validated by the check-toml hook above, and taplo upstream is dormant.
 [[repos]]
 repo = "https://github.com/ComPWA/taplo-pre-commit"
 rev = "v0.9.3"
-hooks = [
-  { id = "taplo-format" },
-  { id = "taplo-lint", exclude = '\.dagger/pyproject\.toml$' },
-]
+hooks = [{ id = "taplo-format" }]
 
 # JSON formatting (prettier for consistent style)
 [[repos]]