feat(forum): rebuild plate, post and compose pages

Match the reference layouts for the remaining forum routes: plate pages
get the blurred header card, moderator row and the affix tab bar with
per-tab filtering, topping posts and moderator-only pending/trash tabs;
post pages get the article shell with breadcrumbs, cover, meta row,
vote box, tag row and footer actions; compose pages get the reference
editor plus settings sidebar (submit/draft, status, access, plate,
topic, tag, type, vote) with a cover picker. Saving now honours draft
state and the featured image through the REST contract.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/js/forum-runtime.js

@@ -95,6 +95,93 @@
   typeSelect?.addEventListener('change', syncType)
   syncType()
 
+  // 发帖页：下拉式设置项（阅读权限 / 版块 / 话题 / 标签 / 类型）统一走隐藏输入。
+  const syncHidden = (name, value) => {
+    root.querySelectorAll(`input[type="hidden"][name="${name}"]`).forEach((input) => { input.value = value })
+  }
+  const syncTypeBox = () => {
+    const box = root.querySelector('.forum-type-vote')
+    const current = root.querySelector('input[type="hidden"][name="type"]')?.value || 'normal'
+    if (box) box.hidden = current !== 'vote'
+  }
+  root.addEventListener('click', (event) => {
+    const type = event.target.closest('[data-forum-type-set]')
+    if (type) {
+      root.querySelectorAll('[data-forum-type-set]').forEach((item) => item.classList.toggle('active', item === type))
+      syncHidden('type', type.dataset.forumTypeSet)
+      syncTypeBox()
+      return
+    }
+    const view = event.target.closest('[data-forum-view]')
+    if (view) {
+      root.querySelectorAll('[data-forum-view]').forEach((item) => item.classList.toggle('active', item === view))
+      syncHidden('view_limit', view.dataset.forumView)
+      const label = root.querySelector('span[name="view_limit"]')
+      if (label) label.textContent = view.textContent.trim()
+      return
+    }
+    const plate = event.target.closest('[data-forum-plate]')
+    if (plate) {
+      root.querySelectorAll('[data-forum-plate]').forEach((item) => item.classList.toggle('active', item === plate))
+      syncHidden('plate_id', plate.dataset.forumPlate)
+      const label = root.querySelector('span[name="plate_id"]')
+      if (label) label.textContent = plate.textContent.trim()
+      return
+    }
+    const status = event.target.closest('[data-forum-status]')
+    if (status) {
+      root.querySelectorAll('[data-forum-status]').forEach((item) => item.classList.toggle('active', item === status))
+      syncHidden('post_status', status.dataset.forumStatus)
+      return
+    }
+    const pick = event.target.closest('[data-forum-cover-pick]')
+    if (pick) {
+      root.querySelector('[data-forum-cover-file]')?.click()
+      return
+    }
+    const draft = event.target.closest('[data-forum-draft]')
+    if (draft) {
+      const form = draft.closest('[data-forum-form]')
+      if (form) {
+        syncHidden('post_status', 'draft')
+        form.requestSubmit()
+      }
+    }
+  })
+  root.addEventListener('change', (event) => {
+    const term = event.target.closest('[data-forum-topics],[data-forum-tags]')
+    if (term) {
+      const field = term.matches('[data-forum-topics]') ? 'topics' : 'tags'
+      const values = [...root.querySelectorAll(`[data-forum-${field}]:checked`)].map((input) => input.value)
+      syncHidden(field, values.join(','))
+      term.closest('label')?.classList.toggle('active', term.checked)
+      const label = root.querySelector(`[data-forum-${field}-label]`)
+      if (label) label.textContent = values.length ? values.slice(0, 2).join('、') : '请选择'
+    }
+  })
+  root.addEventListener('change', async (event) => {
+    const cover = event.target.closest('[data-forum-cover-file]')
+    if (!cover?.files?.[0]) return
+    const data = new FormData()
+    data.append('file', cover.files[0])
+    try {
+      const response = await fetch(config.api + 'upload/image', { method: 'POST', credentials: 'same-origin', headers: { 'X-WP-Nonce': config.nonce }, body: data })
+      const payload = await response.json()
+      if (!response.ok || !payload.success) throw new Error(payload.message || '上传失败')
+      const preview = root.querySelector('.forum-cover-preview')
+      if (preview) {
+        preview.classList.remove('is-empty')
+        preview.innerHTML = '<img src="' + payload.data.url + '" alt="">'
+      }
+      const hidden = root.querySelector('input[name="featured_image_id"]')
+      if (hidden) hidden.value = payload.data.id || ''
+    } catch (error) {
+      message(cover.closest('.edit-posts-featured') || root, error.message)
+    } finally {
+      cover.value = ''
+    }
+  })
+
   const insertMedia = (kind, url, name) => {
     const element = document.createElement(kind === 'image' ? 'img' : kind === 'video' ? 'video' : 'a')
     if (kind === 'resource') { element.href = url; element.textContent = name || '下载附件' }