perf: Lucide subpath imports to split 748 KB icon chunk

Barrel `from '@lucide/svelte'` imports pulled every referenced icon into
one shared 748 KB client chunk. Switch every call site to per-icon
subpaths (`@lucide/svelte/icons/<kebab-name>`) so Vite tree-shakes each
icon independently. Also logs the TODO list for the perf audit so we
don't lose track.

- 46 files, 106 unique icons
- single `Minus as MinusIcon` alias preserved
- Lucide-internal aliases (`AlertTriangle`, `BarChart3`) resolve through
  Lucide's own re-export shims; no behavioral change

TODO.md

@@ -1,5 +1,21 @@
 # TODO
 
+## Perf (audit 2026-04-23)
+
+Order = impact. Font items + app.html preload intentionally skipped.
+
+- [x] 1. Lucide subpath imports — convert `from '@lucide/svelte'` barrel imports to `@lucide/svelte/icons/<kebab-name>` so Vite tree-shakes per-icon (current 748 KB shared chunk)
+- [ ] 2. Chart.js dynamic import in `FitnessChart.svelte` (drop 244 KB from non-stats fitness routes)
+- [ ] 3. Recipe `all_brief` endpoint — drop `JSON.parse(JSON.stringify(...))`, move shuffle client-side, enable caching
+- [ ] 4. Favorites page — drop unnecessary `all_brief` fetch (verify consumer first)
+- [ ] 5. Replace redundant `locals.auth()` with `locals.session` across recipe/calendar/fitness loaders
+- [ ] 6. Stream fitness stats loader — return promises for slow panels
+- [ ] 7. Overview endpoint — add `.select(...)` projection, cap timeseries window
+- [ ] 8. Calendar payload trim — drop `name` from `yearDays`, pre-filter `feastDots` server-side
+- [ ] 9. History sessions endpoint — slim exercise payload for list view
+- [ ] 10. `Cache-Control` headers on stable API endpoints (all_brief, calendar, exercises metadata)
+- [ ] 11. Search — debounce 200 ms + server-side pre-normalized `_searchKey`
+
 ## Features
 [x] on /fitness/measure, fill "Past measurements" in SSR only for the last 10 measurements. anything further should be fetched client side on mount to decreae initial page load time. use a "show more" button and paginate measurments.
 [x] on /fitness/measure (resp. their associated logging API routes), consolidate measurements by day. If we want to log another measurement, overwriting an old one, show a warning to indicate this. disparate measurements (e.g., weight and bodyfat) should not show this warning but simply be merged into one log entry for that day.
@@ -8,6 +24,8 @@
 [x] BF graph (with trend line like weight graph) on /fitness/stats page. Emphasize relative changes, not absolute numbers in design (as we cannot trust those) (e.g., use start day of overview as 0% and then show +/- x % on the graph)
 [x] Workshop better names than "Measure" for the /fitness/measure route. It's about body data points (i.e., non-food related). What's a better, short name than "Measure" to capture the logging of weight, body composition, body part measurements, and period tracking?
 [x] on /fitness/stats/histoy/<part> for body measurement graphs, make the range reasonable. e.g., if we have 1 cm change, do not fill the entire y-height with 1 cm. Use reasonable padding for low ranges (i think we do something like htis already on the weight graph?)
+[ ] Make the Period ended button a lot more prominent
+[ ] swap heart emoji on recipe favorites to lucide icon
 
 ## Refactor Recipe Search Component