v0.5.4

Fixed

• Template parser mirrors thiserror's formatter trait detection, ensuring
  :?, :x, :X, :p, :b, :o, :e and :E specifiers resolve to the
  appropriate TemplateFormatter variant while still flagging unsupported
  flags precisely.

Tests

• Added parser-level unit tests that cover every supported formatter specifier
  and assert graceful failures for malformed format strings.