[ElliotEtag]

Description:

• Preserve Google/Vertex prompt blocks, including Google's documented unspecified block, as explicit errors.
• Preserve zero/omitted output-token usage and reasoning tokens; handle filtered candidates without content parts.
• Retain reported SSE usage on errors for provider-cost tracking without charging callers.
• Billing changes: Vertex JSON blocks change from 200/billed to 422/unbilled; SSE blocks change from 502/unbilled to 422/unbilled in Gen tracking. JSON error cost remains untracked by Gen; Google's invoicing for this Gemini model's blocked prompts is unverified.

Tests Run/Test cases added:

• 27 stream, 47 Vertex and 15 parameter tests; formatting, build and startup checks pass. CI runs parameter and stream tests.
• Nine Gen/auth/wallet/telemetry E2E cases: five live Google calls (SSE, JSON, tools, zero output, filtered output), four native fixtures (documented block in SSE/JSON, mid-stream failure, missing usage).
• Successes debit once; errors debit zero. SSE block/mid-stream errors retain provider cost; missing usage stays 502.
• Local telemetry; JSON uses the inline coordinator helper. Broader tests/typecheck retain main's 8 failing suites and 11 diagnostics.

Type of Change:

• Bug fix

Rollout: bump Pollinations' 9ffc0ef gateway pin after merge; this also ships #15 (Bedrock errors) and #16 (CI). Reverting the pin rolls back.