Constant INDEX_SCRIPT 

const INDEX_SCRIPT: &str = "// Storybook index cockpit (DEV-03 / DEV-08).\n// Vanilla JS, no framework. Loaded inline from export_stories.rs.\n\n(function () {\n  var frame = document.getElementById(\'storybook-index-frame\');\n  var current = document.getElementById(\'storybook-index-current\');\n  var openLink = document.getElementById(\'storybook-index-open\');\n  var filter = document.getElementById(\'storybook-index-filter\');\n  var list = document.querySelector(\'.storybook-index-list\');\n  var FILTER_KEY = \'storybook-index-filter\';\n\n  function pick(id) {\n    if (!id) {\n      id = (document.body.getAttribute(\'data-first-story\') || \'\').trim();\n    }\n    if (!id) return;\n    var safeId = id.replace(/[^a-zA-Z0-9_-]/g, \'\');\n    if (safeId !== id) return;\n    var href = \'./\' + safeId + \'.html\';\n    if (frame.getAttribute(\'src\') !== href) {\n      frame.setAttribute(\'src\', href);\n    }\n    if (current) current.textContent = safeId;\n    if (openLink) openLink.setAttribute(\'href\', href);\n    document.querySelectorAll(\'.storybook-index-row\').forEach(function (row) {\n      if (row.getAttribute(\'data-id\') === safeId) {\n        row.classList.add(\'is-active\');\n      } else {\n        row.classList.remove(\'is-active\');\n      }\n    });\n  }\n\n  function readHash() {\n    return decodeURIComponent((location.hash || \'\').replace(/^#/, \'\'));\n  }\n\n  window.addEventListener(\'hashchange\', function () {\n    pick(readHash());\n  });\n\n  pick(readHash());\n\n  if (list) {\n    list.addEventListener(\'click\', function (e) {\n      var target = e.target;\n      while (target && target !== list && target.tagName !== \'A\') {\n        target = target.parentNode;\n      }\n      if (!target || target === list) return;\n      var id = target.getAttribute(\'data-id\');\n      if (!id) return;\n      // Allow native anchor to update the hash; pick() runs from hashchange.\n    });\n  }\n\n  function applyFilter(query) {\n    var q = (query || \'\').trim().toLowerCase();\n    var anyVisible = false;\n    document.querySelectorAll(\'.storybook-index-row\').forEach(function (row) {\n      var match =\n        !q ||\n        (row.getAttribute(\'data-id\') || \'\').indexOf(q) !== -1 ||\n        (row.getAttribute(\'data-title\') || \'\').indexOf(q) !== -1 ||\n        (row.getAttribute(\'data-category\') || \'\').indexOf(q) !== -1;\n      if (match) {\n        row.classList.remove(\'is-hidden\');\n        anyVisible = true;\n      } else {\n        row.classList.add(\'is-hidden\');\n      }\n    });\n    document.querySelectorAll(\'.storybook-index-category\').forEach(function (cat) {\n      var rows = cat.querySelectorAll(\'.storybook-index-row\');\n      var visible = 0;\n      rows.forEach(function (r) {\n        if (!r.classList.contains(\'is-hidden\')) visible += 1;\n      });\n      if (visible === 0) {\n        cat.classList.add(\'is-hidden\');\n      } else {\n        cat.classList.remove(\'is-hidden\');\n      }\n    });\n    try {\n      window.sessionStorage.setItem(FILTER_KEY, q);\n    } catch (_e) {\n      /* sessionStorage may be unavailable (private mode) */\n    }\n    return anyVisible;\n  }\n\n  if (filter) {\n    try {\n      var stored = window.sessionStorage.getItem(FILTER_KEY) || \'\';\n      if (stored) {\n        filter.value = stored;\n        applyFilter(stored);\n      }\n    } catch (_e) {\n      /* ignore */\n    }\n    filter.addEventListener(\'input\', function () {\n      applyFilter(filter.value);\n    });\n    document.addEventListener(\'keydown\', function (e) {\n      var inField =\n        e.target &&\n        (e.target.tagName === \'INPUT\' ||\n          e.target.tagName === \'TEXTAREA\' ||\n          e.target.isContentEditable);\n      if (e.key === \'/\' && !inField) {\n        e.preventDefault();\n        filter.focus();\n        filter.select();\n      } else if (e.key === \'Escape\' && document.activeElement === filter) {\n        filter.value = \'\';\n        applyFilter(\'\');\n        filter.blur();\n      }\n    });\n  }\n})();\n";