* fix(claude): align Opus 5.5 cloak and preserve native CLI hints
* fix(claude): recognize the 2.1.280 Haiku title helper
The native title request now appends server-side fallback, fallback credit,
and cache diagnosis after the structured-output beta. Keep the helper
allowlist exact so this sequence passes through without cloaking.
* fix(claude): align thinking visibility and Messages passthrough
* fix(claude): preserve thinking visibility through compatibility paths
* fix(claude): harden OAuth beta, session alignment, and 2.1.280 helper headers