feat: regenerate API client from OpenAPI spec

[convoy-sdk-bot]

Automated regeneration via oapi-codegen from docs/v3/openapi3.yaml on frain-dev/convoy main. The hand-written root package and webhook verify are untouched by the sync script.

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Note

Low Risk
Generated client-only changes with no runtime or auth logic; low risk unless callers depend on exact generated signatures.

Overview
Regenerates client/client.gen.go from the OpenAPI spec and adds client support for GET /v1/projects/{projectID}/endpoints/period-failure-rates.

Consumers can call GetEndpointPeriodFailureRates (and the WithResponse variant) with optional endpointId, startDate, and endDate query params. Responses deserialize into the new ModelsEndpointPeriodFailureRate type (per-endpoint UID, success/retry/failure counts, and period_failure_rate).

The endpoint is documented as display-only metrics over a date range (default last 7 days), split from the endpoint list so heavy counts do not block the table.

^{Reviewed by Cursor Bugbot for commit 64fe02e. Bugbot is set up for automated code reviews on this repo. Configure here.}

[convoy-sdk-reviewer]

SDK reviewer app: approving a generated-paths-only diff on the regen branch. Auto-merge completes only after required status checks pass.