Gate `size_to_values()` on macOS in `_axes.py`

NOTE, this reversion was discovered as needed by @goodboy after
extensively manually testing the new zoom-by-font-size feats introduced
alongside macOS support.

Use class-body `if _friggin_macos:` branching to
conditionally define `size_to_values()` for both
`PriceAxis` and `DynamicDateAxis` — macOS gets the
new `_updateWidth()`/`_updateHeight()` + geometry
recalc path, other platforms fall back to the
original `setWidth()`/`setHeight()` calls.

Deats,
- add `platform` import and module-level
  `_friggin_macos: bool` flag.
- `PriceAxis.size_to_values()`: macOS branch calls
  `_updateWidth()` + `updateGeometry()`; else branch
  uses `self.setWidth(self.typical_br.width())`.
- `DynamicDateAxis.size_to_values()`: macOS branch
  calls `_updateHeight()` + `updateGeometry()`; else
  uses `self.setHeight(self.typical_br.height() + 1)`.
- reorder imports: `platform` before `typing`.

(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

piker/ui/_axes.py

@@ -20,8 +20,9 @@ Chart axes graphics and behavior.
 """
 from __future__ import annotations
 from functools import lru_cache
-from typing import Callable
 from math import floor
+import platform
+from typing import Callable
 
 import polars as pl
 import pyqtgraph as pg
@@ -42,6 +43,7 @@ from ._style import DpiAwareFont, hcolor, _font
 from ._interaction import ChartView
 from ._dataviz import Viz
 
+_friggin_macos: bool = platform.system() == 'Darwin'
 _axis_pen = pg.mkPen(hcolor('bracket'))
 
 
@@ -172,6 +174,7 @@ class Axis(pg.AxisItem):
         text_offset = None
         if self.orientation in ('bottom',):
             text_offset = floor(0.25 * font_size)
+
         elif self.orientation in ('left', 'right'):
             text_offset = floor(font_size / 2)
 
@@ -293,6 +296,7 @@ class PriceAxis(Axis):
     ) -> None:
         self._min_tick = size
 
+    if _friggin_macos:
         def size_to_values(self) -> None:
             # Call PyQtGraph's internal width update mechanism
             # This respects autoExpandTextSpace and updates min/max constraints
@@ -303,6 +307,12 @@ class PriceAxis(Axis):
             if self.pi and hasattr(self.pi, 'updateGeometry'):
                 self.pi.updateGeometry()
 
+    else:
+        def size_to_values(self) -> None:
+            # XXX, old code!
+            self.setWidth(self.typical_br.width())
+
+
     # XXX: drop for now since it just eats up h space
 
     def tickStrings(
@@ -344,6 +354,7 @@ class DynamicDateAxis(Axis):
         1: '%H:%M:%S',
     }
 
+    if _friggin_macos:
         def size_to_values(self) -> None:
             # Call PyQtGraph's internal height update mechanism
             # This respects autoExpandTextSpace and updates min/max constraints
@@ -354,6 +365,11 @@ class DynamicDateAxis(Axis):
             if self.pi and hasattr(self.pi, 'updateGeometry'):
                 self.pi.updateGeometry()
 
+    else:
+        def size_to_values(self) -> None:
+            # XXX, old code!
+            self.setHeight(self.typical_br.height() + 1)
+
     def _indexes_to_timestrs(
         self,
         indexes: list[int],