feat(fingerprint): align with CC 2.1.90 betas and fix cache_control overflow

Remove tool-examples-2025-10-29 (dropped upstream), add task-budgets and
token-efficient-tools beta constants, bump fallback version to 2.1.90.
Strip cache_control from incoming system blocks to prevent exceeding the
API's 4-block cache_control limit.

Constraint: API enforces max 4 cache_control blocks per request
Rejected: Passthrough upstream cache_control | causes overflow when CC adds its own markers
Confidence: high
Scope-risk: narrow