UR-Nexus 1.87.3

• Read Claude's live effort and thinking-mode capabilities instead of treating
  current models as unsupported. Thin cached entries retain exact documented
  fallbacks; explicit live capability values remain authoritative.
• Added current Opus, Sonnet, Haiku and Fable capability definitions. Opus 5.5
  and Fable's mandatory thinking is labelled always on; Sonnet 5.5's reduced
  mode uses between_tools, and Haiku 5.5 supports explicit disabling.
• Added Standard/Fast selection to both model pickers (s), applied only when
  confirmed. /fast now controls the selected native model without changing
  models or contacting a hosted UR service. Premium pricing is shown explicitly.
• Opus 5.5 fast mode uses its generally available contract without a beta
  header; Opus 5/4.8 retain their required preview beta. The existing fast-mode
  disable flag is honored by native requests. Updated documentation and added
  metadata, keyboard, persistence and full native request regressions.