chore(deprecation): remove the 35 APIs deprecated for 3.8.0 (#708)

* chore(deprecation): remove the 35 APIs deprecated for 3.8.0

The usage scan (docs/DEPRECATIONS_3.8.md, regenerated 2026-10-01 and
committed here) finds no call or override of any of them in the 46
monorepo plugins or the 8 third-party plugins plugins.json lists; the
only core callers were other deprecated methods removed alongside.

- CacheManager: 13 methods, plus the private helpers only
  has_data_changed used (_has_*_changed, _is_market_open).
- DisplayManager: 7 methods, plus WEATHER_COLORS and the private
  _draw_sun/_cloud/_rain/_snow/_storm helpers only the icon methods used.
- FontManager: 14 methods, plus size_tokens, _save_overrides and
  _clear_plugin_font_cache. font_overrides and _load_overrides stay:
  resolve_font() still applies config/font_overrides.json.
  performance_stats stays: get_font() keeps it and tests read it.
- PluginManager.get_enabled_plugins.

test_deprecation.py pins only the two 3.9.0 markers now; the scanner
tests run against a stand-in core instead of the real markers. The
memory-tier tests read stats through log_memory_cache_stats() and the
component, and the test of the removed _clear_plugin_font_cache goes.
Docs drop the removed methods' reference entries; the Deprecated APIs
table becomes "Removed in 3.8.0". CHANGELOG gains a Removed section.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* chore(deprecation): drop the test harness's copies of the removed icon methods

VisualTestDisplayManager still drew weather icons that DisplayManager no
longer has, so a plugin's visual tests could pass on calls that raise
AttributeError on the real display. Its draw_sun/draw_cloud/draw_rain/
draw_snow/draw_weather_icon/draw_text_with_icons, WEATHER_COLORS and the
private helpers go, with the tests that exercised them. The CHANGELOG's
Deprecations entries no longer say nothing is removed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/FONT_MANAGER.md

@@ -13,10 +13,9 @@
 BDF fonts in `assets/fonts/`, registers fonts that plugins ship, and records
 which plugin uses which font so the web UI can show it.
 
-Several methods are deprecated and will be removed in LEDMatrix 3.8.0; they
-log a warning on first call. They are listed in
-[Deprecated methods](#deprecated-methods) below, and the full set is pinned in
-[`test/test_deprecation.py`](../test/test_deprecation.py).
+Several methods were removed in LEDMatrix 3.8.0 after a release of
+deprecation warnings; [Removed methods](#removed-methods) below lists them
+with what to use instead.
 
 ## Getting the FontManager
 
@@ -128,8 +127,8 @@ font = self.font_manager.resolve_font(
 
 `resolve_font()` still honours `config/font_overrides.json` (a map of
 element key to `family` and/or `size_px`), which is read once at start-up.
-The methods that edit it — `set_override()`, `remove_override()`,
-`get_overrides()` — are deprecated, and there is no web UI or REST endpoint
+The methods that edited it — `set_override()`, `remove_override()`,
+`get_overrides()` — were removed in 3.8.0, and there is no web UI or REST endpoint
 for overrides (the override editor and `/api/v3/fonts/overrides` were
 removed). To let users choose a font, add a field to your plugin's config
 schema.
@@ -207,9 +206,10 @@ Current methods:
 | `clear_cache()` | Drop cached fonts and metrics |
 | `font_catalog` (attribute) | Family name → file path |
 
-### Deprecated methods
+### Removed methods
 
-Removed in 3.8.0. Each logs a warning on first call.
+Removed in 3.8.0, after logging a deprecation warning on first call since
+3.5.0.
 
 | Method | Use instead |
 |---|---|