✨ feat(vscode): 摘修复识别 alembic 迁移，接不上发布分支链的高亮禁用不可摘

按 writing-alembic-migrations 的规矩判断：迁移的前任必须已在发布分支上，
且发布分支上该前任不能已有别的后继；根迁移接不上已有链、删迁移会断链也不可摘。
列表里带迁移的提交打「迁移」角标，不可摘的高亮警告色、禁用勾选并写明原因；
确认接口再校验一遍，绕过前端也摘不进去。

Claude-Session: https://claude.ai/code/session_01QWxLb6X8Vd2G5vHnp6R7qm

vscode/webview-ui/src/components/CherryPickModal.tsx

@@ -1,7 +1,7 @@
 import type { ReleaseCommitGroup } from '../lib/messages'
 import { ChevronRight, X } from 'lucide-react'
 import { useEffect, useMemo, useState } from 'react'
-import { filterCherryPickGroups, groupContainingSha, uniqueAuthors } from '../lib/cherryPickView'
+import { filterCherryPickGroups, groupContainingSha, pickableShas, uniqueAuthors } from '../lib/cherryPickView'
 
 interface Props {
   open: boolean
@@ -78,7 +78,7 @@ export function CherryPickModal({ open, branch, groups, firstAfterReleaseSha, on
   }
 
   function toggleGroupSelected(g: ReleaseCommitGroup): void {
-    const shas = g.commits.map(c => c.sha)
+    const shas = pickableShas(g.commits)
     const allOn = shas.every(s => selected.has(s))
     setSelected((prev) => {
       const next = new Set(prev)
@@ -150,7 +150,8 @@ export function CherryPickModal({ open, branch, groups, firstAfterReleaseSha, on
             : visible.map((g) => {
                 const key = groupKey(g)
                 const openGroup = query.trim() !== '' || expanded.has(key)
-                const shas = g.commits.map(c => c.sha)
+                const shas = pickableShas(g.commits)
+                const blockedCount = g.commits.length - shas.length
                 const allOn = shas.length > 0 && shas.every(s => selected.has(s))
                 const someOn = shas.some(s => selected.has(s))
                 return (
@@ -171,11 +172,13 @@ export function CherryPickModal({ open, branch, groups, firstAfterReleaseSha, on
                         </span>
                         <span className="shrink-0 text-[11px] opacity-60">
                           {`${g.authors.join(' · ')} · ${g.commits.length} 条`}
+                          {blockedCount > 0 ? ` · ${blockedCount} 条带迁移不可摘` : ''}
                         </span>
                       </button>
                       <input
                         type="checkbox"
                         checked={allOn}
+                        disabled={shas.length === 0}
                         ref={(el) => {
                           if (el)
                             el.indeterminate = someOn && !allOn
@@ -187,25 +190,47 @@ export function CherryPickModal({ open, branch, groups, firstAfterReleaseSha, on
                     </div>
                     {openGroup && (
                       <ul className="border-t border-[var(--vscode-panel-border)] py-1">
-                        {g.commits.map(c => (
-                          <li key={c.sha}>
-                            <label className={`flex cursor-pointer items-start gap-2 px-3 py-1.5 hover:bg-white/5 ${c.sha === firstAfterReleaseSha ? 'bg-[var(--vscode-editor-findMatchHighlightBackground)]' : ''}`}>
-                              <input
-                                type="checkbox"
-                                checked={selected.has(c.sha)}
-                                onChange={() => toggleSha(c.sha)}
-                                className="mt-0.5"
-                              />
-                              <span className="min-w-0 flex-1">
-                                <span className="block truncate">{c.subject}</span>
-                                <span className="block text-[11px] opacity-60">
-                                  {`${c.sha.slice(0, 7)} · ${c.author} · ${c.date}`}
-                                  {c.sha === firstAfterReleaseSha ? ' · 发布点后第一条' : ''}
+                        {g.commits.map((c) => {
+                          const blocked = c.migration?.blocked
+                          const rowBg = blocked
+                            ? 'bg-[var(--vscode-inputValidation-warningBackground)]'
+                            : c.sha === firstAfterReleaseSha ? 'bg-[var(--vscode-editor-findMatchHighlightBackground)]' : ''
+                          return (
+                            <li key={c.sha}>
+                              <label className={`flex items-start gap-2 px-3 py-1.5 ${blocked ? 'cursor-not-allowed' : 'cursor-pointer hover:bg-white/5'} ${rowBg}`}>
+                                <input
+                                  type="checkbox"
+                                  checked={selected.has(c.sha)}
+                                  disabled={!!blocked}
+                                  onChange={() => toggleSha(c.sha)}
+                                  className="mt-0.5"
+                                />
+                                <span className="min-w-0 flex-1">
+                                  <span className="flex min-w-0 items-center gap-1.5">
+                                    {c.migration && (
+                                      <span
+                                        title={c.migration.files.join('\n')}
+                                        className="shrink-0 rounded border border-current px-1 text-[10px] leading-4 opacity-80"
+                                      >
+                                        迁移
+                                      </span>
+                                    )}
+                                    <span className="min-w-0 flex-1 truncate">{c.subject}</span>
+                                  </span>
+                                  <span className="block text-[11px] opacity-60">
+                                    {`${c.sha.slice(0, 7)} · ${c.author} · ${c.date}`}
+                                    {c.sha === firstAfterReleaseSha ? ' · 发布点后第一条' : ''}
+                                  </span>
+                                  {blocked && (
+                                    <span className="block text-[11px] text-[var(--vscode-editorWarning-foreground)]">
+                                      {`不可摘：${blocked}`}
+                                    </span>
+                                  )}
                                 </span>
-                              </span>
-                            </label>
-                          </li>
-                        ))}
+                              </label>
+                            </li>
+                          )
+                        })}
                       </ul>
                     )}
                   </section>