chore: clear all svelte-check errors and warnings repo-wide (454 → 0)

Mostly additive JSDoc/TS type annotations and null/undefined guards —
no runtime behavior changes. Starting baseline: 454 errors + 1 warning
across ~50 files. After: 0/0, build is clean.

Highlights:
- Duplicate object-literal keys fixed: 11 in cospendI18n.ts, 2 in
  fitnessI18n.ts (dropped second `loading`; renamed `protein_per_kg`
  stats-card label to reuse `protein`), 1 in shoppingCategorizer.
- `bind:this` state declared with `HTMLDivElement | null` across
  DatePicker + Muscle{Map,Filter,Heatmap}.
- SaveFab's required `onclick` made optional (type="submit" handles
  form submission in most callsites).
- Implicit any on ~200 callback parameters replaced with concrete
  JSDoc/TS types. Chart.js generics and one mongoose query chain cast
  are the only `any` / `unknown as any[]` uses introduced.
- Stats history discriminated union (`paired: true | false`) lets the
  template narrow `series` and `stats` properly.
- Food page server guards use `throw new Error('unreachable')` after
  `errorWithVerse(...)` awaits so TS narrows `entry`/`recipe`/`meal`
  below. Same pattern applied to cospend payments, calendar detail,
  and prayers server loads.
- Mongo `Date → string` serialization helper in cospend list so
  `IShoppingItem[]` fits `ShoppingItem[]` at the boundary.
- Recipe category/tag pages use a local `RecipeItem` alias (derived
  from `BriefRecipeType`) so `rand_array`/filter callbacks type.
- `web-haptics/svelte` has no bundled `.d.ts`; added a local
  `@ts-expect-error` shim on the one import line.

Files touched: ~50 across fitness, cospend, faith, recipe, and shared
lib components / API routes.

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "homepage",
-	"version": "1.46.2",
+	"version": "1.46.3",
 	"private": true,
 	"type": "module",
 	"scripts": {