v0.3.0

Changed

• TUI redesigned with a lazygit / nvim-inspired two-pane layout: bordered menu
  and content panels, accent border that follows keyboard focus, the
  tokyo-night theme, and vim-style navigation (j/k, Tab, r, g/G)
• TUI profile view now shows every non-empty field (works for both
  undergraduate and graduate records), and semester views (课表 / 考试安排 /
  实验成绩) gained an inline semester input with Enter-to-refresh

Fixed

• Profile.Schema().dump() (and therefore the TUI profile view and the MCP
  get_profile tool) no longer crashes with AttributeError when a typed
  field — stu_type, gender, a date, or exam-time — is None (common for
  graduate accounts whose 学生类别 value is not a recognised enum); these
  fields now serialise to an empty value
• TUI no longer raises DuplicateIds when switching between menu items: content
  is now swapped only after the previous widgets are fully removed
• TUI course library view now reads the paged result correctly (it previously
  iterated the result dict's keys instead of the course list)
• TUI data tables are now built on the UI thread, fixing a NoActiveAppError
  that could occur when a worker thread constructed the widget
• TUI startup no longer crashes on systems without an OS keyring backend;
  auto-login is skipped and the user is warned that the password cannot be saved
• Rapidly switching menu items no longer renders a stale result over a newer one