Initial plan commit

frontend/src/lib/stores.svelte.js

@@ -0,0 +1,14 @@
+/**
+ * Shared state lives in stores, not prop-drilling (spec §8.2 rule 3).
+ * Mutation flow: component → api.js → update store from the response.
+ * Svelte 5 runes style only (spec §8.2 rule 8).
+ */
+
+// Current date as a YYYY-MM-DD string — the server never decides "today" (spec §8.1 rule 8)
+export const currentDate = $state({
+  value: new Date().toISOString().slice(0, 10),
+})
+
+// Today's log entries and current target, refreshed from the API after any mutation
+export const todayLog = $state({ entries: [], loading: false, error: null })
+export const currentTarget = $state({ target: null, loading: false, error: null })