fix(testing): harness calendar_font is sized like the panel's

VisualTestDisplayManager built its 5x7 calendar_font / bdf_5x7_font as a
bare freetype.Face. With no size set its ascender reads 0, so BDF text
drawn with it landed 6px above where DisplayManager draws it -- entirely
off the canvas at y=0 -- and get_font_height() returned 0. Golden images
and check_plugin / dev_server previews showed text the panel does not.

Load it through load_bdf_face at the panel's 7px, so it is the very face
DisplayManager uses. Across the differential run this changes only the
cases drawn with the harness's own calendar_font (968 of 220,032), which
now match the panel's output.

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

CHANGELOG.md

@@ -38,7 +38,11 @@ accepts both, but the store flags the old spelling as deprecated
   the file's native strike) and `draw_bdf_text(draw, text, x, y, face, color)`.
   `DisplayManager`, `FontManager`, `element_style` and the plugin test harness
   now all load and draw BDF text through it; the panel's pixels are unchanged
-  and BDF text draws 10-250x faster.
+  and BDF text draws 10-250x faster. The plugin test harness's
+  `calendar_font` / `bdf_5x7_font` now has the panel's 7px size set: it used
+  to be an unsized face, so in golden images and `check_plugin` /
+  `dev_server` previews its text sat 6px above where the panel draws it (off
+  the canvas entirely near the top) and `get_font_height()` returned 0.
 
 - The web UI's Fonts tab has a **Used by** column: the loaded plugins that
   registered each font with `FontManager.register_manager_font()`, published

src/plugin_system/testing/visual_display_manager.py

@@ -22,8 +22,8 @@ process_deferred_updates, update_display, render_size. A behavior
 change to any of those in DisplayManager must be mirrored here, or
 plugin visual tests will pass against stale behavior.
 
-BDF glyphs are not mirrored: both classes draw them through
+BDF text is not mirrored: both classes load BDF faces and draw BDF glyphs
-src/common/bdf_font.py, so those pixels cannot drift.
+through src/common/bdf_font.py, so those pixels cannot drift.
 """
 
 import math
@@ -34,7 +34,7 @@ from pathlib import Path
 from typing import Any, List, Optional, Tuple
 
 from PIL import Image, ImageDraw, ImageFont
-from src.common.bdf_font import draw_bdf_text
+from src.common.bdf_font import draw_bdf_text, load_bdf_face
 from src.common.font_layout import crisp_size, load_truetype
 
 from src.logging_config import get_logger
@@ -151,16 +151,18 @@ class VisualTestDisplayManager:
             self.small_font = load_truetype(ttf_path, crisp_size(press_start, 8))
             self.font = self.regular_font  # alias used by some code paths
 
-            # 5x7 BDF font via freetype
+            # 5x7 BDF font, loaded exactly as DisplayManager._load_fonts does
+            # (same loader, same 7px request as its _CALENDAR_FONT_PX). A bare
+            # freetype.Face has no active size, so its ascender reads 0 and
+            # every line drew a baseline too high.
             try:
-                import freetype
                 bdf_path = str(fonts_dir / '5x7.bdf')
                 if not os.path.exists(bdf_path):
                     raise FileNotFoundError(f"BDF font not found: {bdf_path}")
-                face = freetype.Face(bdf_path)
+                face, _ = load_bdf_face(bdf_path, 7)
                 self.calendar_font = face
                 self.bdf_5x7_font = face
-            except (ImportError, FileNotFoundError, OSError) as e:
+            except Exception as e:  # freetype missing or the file unloadable
                 logger.debug("BDF font not available, using small_font as fallback: %s", e)
                 self.calendar_font = self.small_font
                 self.bdf_5x7_font = self.small_font

test/test_bdf_font.py

@@ -188,6 +188,18 @@ def test_display_manager_and_test_harness_draw_the_reference_pixels(name):
         _assert_same(ref, vt.image, ("VisualTestDisplayManager", name, text))
 
 
+def test_harness_calendar_font_is_the_panels():
+    # The harness built a bare freetype.Face with no size: ascender 0, so
+    # every calendar_font line drew a baseline too high, and its
+    # get_font_height() returned 0.
+    from src.plugin_system.testing.visual_display_manager import VisualTestDisplayManager
+
+    vt = VisualTestDisplayManager(64, 32)
+    panel_face, _ = load_bdf_face(str(FONTS_DIR / "5x7.bdf"), 7)
+    assert vt.calendar_font is panel_face
+    assert vt.get_font_height(vt.calendar_font) == panel_face.size.height >> 6 > 0
+
+
 # -------------------------------------------------------------------- loader
 
 def test_off_strike_size_loads_the_native_strike():