refactor(storybook): hide page headers and preserve accessibility

StoryPageHeader no longer shows the page title, kicker, description or the SW group notice; it renders only a visually hidden H1 with the Story title, so the preview keeps a page heading for screen readers while the first section starts at the top gutter (unchanged position).

- OrgChart verify-p8 / p9 / p9-1 / p9-2-composition wait for the first visible StoryPage content block and read the page H1 instead of .sb-page-title; existing expectations are unchanged.
- SW overview browser test clicks the page gutter as its outside-click target.
- Drop the unused .sb-page-description from the SW Storybook hide rules.
- Update the Storybook page frame rule in the project guideline.

examples/org-chart/verify-p9-1.mjs

@@ -39,7 +39,8 @@ async function settle() {
 async function goto(name, size) {
   await page.setViewportSize(size);
   await page.goto(`${origin}/iframe.html?id=${stories[name]}&viewMode=story`);
-  await page.locator('.sb-page-title').waitFor();
+  // The page title is a visually hidden H1 (2026-11-11): wait for the first visible StoryPage content block instead.
+  await page.locator('.sb-page-inner > :not(h1)').first().waitFor();
   await page.waitForFunction(() => {
     const hosts = [...document.querySelectorAll('.hm-orgchart-host,.hm-orgchart-component-host')];
     return hosts.length === 1 && hosts.every(host => host.shadowRoot && !host.shadowRoot.querySelector('[aria-busy="true"]') && [...host.shadowRoot.querySelectorAll('link[rel="stylesheet"]')].every(link => link.sheet));
@@ -86,7 +87,7 @@ async function snapshot() {
       const css = getComputedStyle(element);
       return { scrollWidth: element.scrollWidth, clientWidth: element.clientWidth, scrollHeight: element.scrollHeight, clientHeight: element.clientHeight, left: element.scrollLeft, top: element.scrollTop, overflowX: css.overflowX, overflowY: css.overflowY };
     };
-    const common = Object.fromEntries(['.sb-page', '.sb-page-inner', '.sb-page-title', '.sb-page-section-title', '.sb-page-section-header', '.sb-page-section-body'].map(selector => [selector, style(document.querySelector(selector))]));
+    const common = Object.fromEntries(['.sb-page', '.sb-page-inner', '.sb-page-inner > h1', '.sb-page-section-title', '.sb-page-section-header', '.sb-page-section-body'].map(selector => [selector, style(document.querySelector(selector))]));
     // Page/section height is content-dependent; typography, borders and gutters are invariant.
     for (const value of Object.values(common)) if (value) for (const key of ['height', 'minHeight']) delete value[key];
     const documentScroll = { viewportWidth: innerWidth, viewportHeight: innerHeight, root: scroll(document.documentElement), body: scroll(document.body), scrollingElement: scroll(document.scrollingElement) };
@@ -145,7 +146,7 @@ async function snapshot() {
       };
     }
     return {
-      title: document.querySelector('.sb-page-title')?.textContent, common, documentScroll, departments, unwanted,
+      title: document.querySelector('.sb-page-inner > h1')?.textContent, common, documentScroll, departments, unwanted,
       optionsPresent: [...document.querySelectorAll('button')].filter(visible).some(button => /긴 이름 검증/.test(button.textContent)),
       sectionTitles: [...document.querySelectorAll('.sb-page-section-title')].map(element => element.textContent), fixed,
     };