Moves the 35 @deprecated markers from 3.7.0 (already shipped with them in
place) to 3.8.0, and adds scripts/plugin_api_usage.py plus the generated
docs/DEPRECATIONS_3.8.md: who still calls or overrides each deprecated
method across core, the monorepo and third-party plugins. Removes nothing.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
35 methods on CacheManager, DisplayManager, FontManager and PluginManager
have no caller in core, the ledmatrix-plugins monorepo or the registry's
third-party plugins, but plugins live elsewhere, so they stay for one
release. src.deprecation.deprecated logs a warning (and emits a
DeprecationWarning) the first time each is called in a process, naming the
release that removes it. The list and replacements are in CHANGELOG and
PLUGIN_API_REFERENCE's new Deprecated APIs section; a test pins the set.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
