Deckard v0.5.0

Adds larger token-aware context windows alongside existing short-passage scanning. Either pass can mark text, with cached threshold updates and overlapping highlights handled together. The default threshold is now 97; saved custom thresholds and On/Off settings are preserved. Native protocol 3 and scanner contract 7 require reloading the unpacked extension and refreshing existing pages after upgrading. Includes owned-installation upgrade support from v0.4.0 and v0.4.1. Apple Silicon macOS 15+; ad-hoc signed, not Developer ID signed or notarized. Detection remains experimental and is not proof of AI authorship.