Format entire codebase with Prettier (mechanical, no behavior change)

docs/architecture/01-state-and-stores.md

@@ -15,7 +15,7 @@ not components" architecture, and it carries no build-time magic. The principles
 are the durable part — they would survive a change of library.
 
 **Lineage (why React + Zustand).** The UI began on Preact + `@preact/signals` and migrated to
-**React + Zustand** at M0, before feature work. The driver was *React-ecosystem friction* —
+**React + Zustand** at M0, before feature work. The driver was _React-ecosystem friction_ —
 real-React-only libraries not cooperating with `preact/compat` — **not** the signals model.
 Switching framework while nothing was implemented yet was also the one cheap moment to pick
 the lowest-migration-risk state library, so signals gave way to Zustand. A bonus: borrowing
@@ -58,7 +58,7 @@ Three ways to touch a store:
 - **`set(partial)`** — update state (shallow-merges). Inside actions, the only place
   that mutates state.
 - **`get()`** — read current state inside actions without subscribing.
-- **the hook `useAppStore(selector)`** — read state *in a React component*, subscribing
+- **the hook `useAppStore(selector)`** — read state _in a React component_, subscribing
   to exactly what the selector returns.
 
 ### Reading in components — always select narrowly
@@ -93,9 +93,11 @@ Services, orchestration, infrastructure, and tests use the store object directly
 no React involved. This is the property that lets our logic live outside components:
 
 ```ts
-openModal('settings');                          // via the modal coordinator (doc 03)
-const theme = useAppStore.getState().uiTheme;  // snapshot read
-const unsub = useAppStore.subscribe((s, prev) => { /* react to changes */ });
+openModal('settings'); // via the modal coordinator (doc 03)
+const theme = useAppStore.getState().uiTheme; // snapshot read
+const unsub = useAppStore.subscribe((s, prev) => {
+  /* react to changes */
+});
 ```
 
 > Rule: in components, **select narrowly** (and `useShallow` for object/array
@@ -106,7 +108,7 @@ const unsub = useAppStore.subscribe((s, prev) => { /* react to changes */ });
 
 ## 2. One Source of Truth per Fact — Derive, Don't Duplicate
 
-Every fact lives in exactly one state field. Anything that can be *calculated*
+Every fact lives in exactly one state field. Anything that can be _calculated_
 from other state is computed **in a selector at read time**, never stored as a
 second field you keep in sync by hand.
 
@@ -121,8 +123,8 @@ read, drift is structurally impossible.
 //   activeSnippetId: string | null
 
 // Derive in the component's selector — not a stored field:
-const activeSnippet = useSnippetStore((s) =>
-  s.snippets.find((x) => x.id === s.activeSnippetId) ?? null,
+const activeSnippet = useSnippetStore(
+  (s) => s.snippets.find((x) => x.id === s.activeSnippetId) ?? null,
 );
 const snippetCount = useSnippetStore((s) => s.snippets.length);
 ```
@@ -141,13 +143,13 @@ const active = useSnippetStore(selectActiveSnippet);
 ```
 
 > Rule: if you can compute it, do not store it. Add a new state field only for a
-> value that is *input* the app receives, not output it derives.
+> value that is _input_ the app receives, not output it derives.
 
 ---
 
 ## 3. Where State Lives: Central vs. Per-Feature Stores
 
-Each store is its own `create()` module. We split by *concern*, not by component
+Each store is its own `create()` module. We split by _concern_, not by component
 tree.
 
 ### Per-feature stores
@@ -162,16 +164,16 @@ Each cohesive feature owns a store holding its durable domain state.
 
 ### The central `useAppStore`
 
-`useAppStore` holds only *cross-cutting, ephemeral UI state* that no single
+`useAppStore` holds only _cross-cutting, ephemeral UI state_ that no single
 feature owns — which modal is open, the runtime theme, transient render flags.
 
 ### How to decide
 
-| Put it in a **feature store** when…           | Put it in **`useAppStore`** when…             |
-| --------------------------------------------- | --------------------------------------------- |
-| It's domain data (snippets, datasets, specs)  | It's transient UI chrome (open modal, theme)  |
-| It outlives a single interaction              | It belongs to no single feature               |
-| It gets persisted                             | Multiple unrelated features read/write it     |
+| Put it in a **feature store** when…          | Put it in **`useAppStore`** when…            |
+| -------------------------------------------- | -------------------------------------------- |
+| It's domain data (snippets, datasets, specs) | It's transient UI chrome (open modal, theme) |
+| It outlives a single interaction             | It belongs to no single feature              |
+| It gets persisted                            | Multiple unrelated features read/write it    |
 
 > Rule: keep `useAppStore` small. When a chunk of it only ever serves one feature,
 > that's the signal to extract a feature store. A bloated central store is the
@@ -253,7 +255,14 @@ export function SnippetList() {
       {snippets.map((s) => (
         <li key={s.id} aria-current={s.id === activeSnippetId} onClick={() => select(s.id)}>
           {s.name}
-          <button onClick={(e) => { e.stopPropagation(); remove(s.id); }}>✕</button>
+          <button
+            onClick={(e) => {
+              e.stopPropagation();
+              remove(s.id);
+            }}
+          >
+            ✕
+          </button>
         </li>
       ))}
     </ul>
@@ -310,7 +319,9 @@ Subscribers read state and write to `src/app/infrastructure/` adapters (IndexedD
 
 ```ts
 // src/main.tsx
-const applyTheme = (t: string) => { document.documentElement.dataset.theme = t; };
+const applyTheme = (t: string) => {
+  document.documentElement.dataset.theme = t;
+};
 applyTheme(useAppStore.getState().uiTheme);
 useAppStore.subscribe((s, prev) => {
   if (s.uiTheme !== prev.uiTheme) applyTheme(s.uiTheme);