fix(files): the review's fixes for the Files panel delete

The fixes #529's review asked for, each with a test.

- No inline handler. The button quoted the path inside
  onclick="...decodeURIComponent('<path>')", and encodeURIComponent leaves
  ' alone, so a file named x'-alert(1)-'.txt ran script in Codeman's
  origin and it's.txt was a syntax error. It is now bound in the existing
  .file-tree-item loops from the row's escaped data-path.
- Symbolic links are refused, never followed. validateSessionFilePath()
  returns the realpath, so deleting AGENTS.md -> CLAUDE.md deleted
  CLAUDE.md and left the link dangling. The path as named is lstat'ed,
  a link answers 400, and the inode is compared again before the unlink.
- The edit route's confinement whole: validateLocalSessionFilePath()
  behind withGuardedOutsideWorktree(), so an absolute path in a followed
  outside worktree obeys the same rules, and the sensitive, blocked and
  .git checks run on both the realpath and the path as named.
- Adopted sessions are refused like remote ones (the /tmp exception of
  the older file surfaces is not copied to a new one); Docker workspaces
  are allowed, as on the edit route. The workspace is probed bounded
  first (#516). Errors are thrown with their status.
- Deleting from search results re-runs the search, the row buttons stay
  visible on touch screens, the confirm and toasts have zh-CN text, and
  no button is drawn for remote or adopted sessions.
- Docs: CLAUDE.md, architecture-invariants, api-reference and the
  Working With Files wiki page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/types/common.ts

@@ -115,6 +115,12 @@ export interface FileWriteData {
   eol: 'lf' | 'crlf';
 }
 
+/** Response payload for `DELETE /api/sessions/:id/files?path=` (the Files panel's delete button). */
+export interface FileDeleteData {
+  /** The path as submitted (workspace-relative, or absolute inside the session's outside worktree) */
+  path: string;
+}
+
 export type CleanupResourceType = 'timer' | 'interval' | 'watcher' | 'listener' | 'stream';
 
 /**