feat: timer unit selector + fix ingredient list alignment (v0.56.0)

Step timer input was seconds-only, no unit — a 90-minute braise meant
typing 5400. Added a seconds/minutes/hours <select> next to the input;
StepRow gets a timerUnit field, converted to seconds at submit. Editing
an existing recipe (and the AI-regenerate flow) picks the largest unit
that divides evenly into the stored seconds so it displays naturally
instead of always falling back to raw seconds.

Ingredient list (serving-scaler.tsx): the quantity column used
min-w-[3rem] on a flex child, which is only a *minimum* — any row whose
formatted quantity text (e.g. an appended "(~2 tbsp)" conversion) exceeded
that width pushed just that row's ingredient name further right,
breaking alignment across the list. Switched the list to a CSS grid with
`display: contents` on each <li>, so the quantity column's width is
shared across every row instead of sized per-row.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "epicure",
-  "version": "0.55.3",
+  "version": "0.56.0",
   "private": true,
   "scripts": {
     "dev": "pnpm --filter web dev",