Fix bugs found in local testing

- Dashboard auto-refresh rendered the full layout into its own
  refresh container, producing a duplicate sidebar every 60s; it now
  renders only the body partial.
- 'Run Now' runs synchronously with a bounded timeout and returns
  refreshed results plus success/error feedback, instead of
  firing-and-forgetting with no signal.
- Price-history chart data moved from a <script> block to a data-
  attribute: templ does not interpolate expressions inside <script>
  element content, so the JSON was emitted literally.
- The htmx indicator spinner was permanently visible due to CSS
  source order; the indicator rules now follow .v-spinner.

Also refreshes README for this session's changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

templates/items.templ

@@ -124,9 +124,12 @@ templ itemRow(it models.Item, csrf string) {
 					}
 				</button>
 			</form>
-			<form class="inline" hx-post={ fmt.Sprintf("/items/%d/run", it.ID) } hx-target={ fmt.Sprintf("#item-row-%d", it.ID) } hx-swap="outerHTML">
+			<form class="inline" hx-post={ fmt.Sprintf("/items/%d/run", it.ID) } hx-target={ fmt.Sprintf("#item-row-%d", it.ID) } hx-swap="outerHTML" hx-disabled-elt="find button">
 				<input type="hidden" name="csrf_token" value={ csrf }/>
-				<button class="v-btn-ghost text-sm" type="submit">Run Now</button>
+				<button class="v-btn-ghost text-sm" type="submit">
+					Run Now
+					<span class="v-spinner htmx-indicator ml-1"></span>
+				</button>
 			</form>
 			<a class="v-btn-ghost text-sm" href={ templ.SafeURL(fmt.Sprintf("/items/%d/edit", it.ID)) }>Edit</a>
 			<form class="inline" hx-post={ fmt.Sprintf("/items/%d/delete", it.ID) } hx-target={ fmt.Sprintf("#item-row-%d", it.ID) } hx-swap="outerHTML" hx-confirm="Delete this item?">