spa hardening, offline logging, rate limit fixes

server:
- backup exporter, auth extractors, error shapes, CONTEXT (prior work)
- spa assets served outside the rate limit via route_layer
- requests_per_second went to per_second(), which takes an interval not a
  rate: 50 meant one request per 50s once burst was spent. now converted
  properly. 15/s, burst 60

spa fixes:
- account delete cleared snake_case token keys that were never written
- refresh interceptor could retry forever
- date ranges used local day boundaries stamped +00:00
- "all" period trend plotted one page; calendar days fabricated mood 3
- chart grid invisible: hsl(var(--border)) against rgba tokens
- blob url leak, orphaned media on failed save, devtools in prod bundle
- pt-safe/safe-area-pb classes never existed

spa features:
- offline outbox: entries queue to IndexedDB, replay with backoff, only
  server refusals count against an entry
- drafts persist, quick-log sheet, diary infinite scroll + filters
- route error boundary, stale-chunk recovery, no service worker in dev

a11y + perf:
- mood picker is a radiogroup, activity picker keyboard-operable,
  text alternatives for colour/emoji, locale week start
- dark glass over the bright photo: worst case 1.4:1 -> 4.9-9.6:1
- initial payload 1095->769kB raw, 306->230kB gzip; 38 unused components
  and 5 deps dropped; fonts 218->133kB

53 tests added (43 spa, 10 server)

spa/tests/lib/media.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, it } from "vitest"
+import {
+  existingIds,
+  existingItem,
+  keyOf,
+  newPendingItem,
+  pendingFiles,
+} from "@/lib/media"
+
+const file = (name: string) => new File(["x"], name, { type: "image/jpeg" })
+
+describe("media items", () => {
+  it("separates what the server holds from what is still local", () => {
+    const items = [existingItem("on-server"), newPendingItem(file("new.jpg"))]
+
+    expect(existingIds(items)).toEqual(["on-server"])
+    expect(pendingFiles(items).map((each) => each.name)).toEqual(["new.jpg"])
+  })
+
+  it("gives every pending item its own key", () => {
+    const first = newPendingItem(file("a.jpg"))
+    const second = newPendingItem(file("a.jpg"))
+
+    expect(keyOf(first)).not.toBe(keyOf(second))
+  })
+
+  it("keys an existing item by its server id", () => {
+    expect(keyOf(existingItem("photo-7"))).toBe("photo-7")
+  })
+})