feat(medications): accept units per dose like 1.5 and let the editor enter them

A medication's units per dose, a schedule's override and a restored
backup now accept any value above 0 and at most 100 with at most four
decimal places, which is exactly what the Decimal(10,4) column stores.
Before, only whole numbers 1-100 and the fractions 1/4, 1/3, 1/2, 2/3,
3/4 passed, so one and a half tablets could not be recorded. A restore
now refuses a value no write route would accept.

The medication editor keeps its buttons and adds an Other field that
reads 1.5, 1,5, 1 1/2 and 1½, holds the step while the text does not
read, and previews the value it will save. The supply tab's packaging
dialog uses the same reader; it refused every non-whole value before,
so a medication at half a tablet could not have its packaging saved.
Cards and the supply tab show a whole number plus a fraction as 1½.

The rule, the input reader and the display format live in one module
without imports so the editor and the validators share them.

Refs #1034

src/lib/openapi/routes/medications/schemas.ts

@@ -152,7 +152,7 @@ export const medicationResource = z
     unitsPerDose: z
       .number()
       .describe(
-        "v1.16.10 — inventory units one dose consumes (e.g. 2 tablets of 2 mg for a 4 mg dose). v1.16.12 — may be a split-pill fraction (¼ / ⅓ / ½ / ⅔ / ¾); thirds carry as ≈0.3333 / 0.6667. Default 1. The intake consumption hook decrements this many units per taken dose; dose-derived readouts divide unit counts by it.",
+        "v1.16.10 — inventory units one dose consumes (e.g. 2 tablets of 2 mg for a 4 mg dose). v1.16.12 — may be a split-pill fraction (¼ / ⅓ / ½ / ⅔ / ¾); thirds carry as ≈0.3333 / 0.6667. v1.39.1 (#1034) — any value above 0 and at most 100 with at most 4 decimal places, so also a whole number plus a fraction (1.5, 2.25, 1.3333) or a measured amount (0.8). Default 1. The intake consumption hook decrements this many units per taken dose; dose-derived readouts divide unit counts by it.",
       ),
     reorderLeadDays: z
       .number()