* feat(task-stats): add oldest_excluding_retries to task stats

Expose oldest_excluding_retries alongside oldest in GetTaskStats so
callers can find the oldest queued task still on its first attempt
(retry_count = 0). Threaded through the SQL query, Go repository/API
transformer, OpenAPI schema, and the Python SDK model.

* chore: drop hand-edited generated files (regen via sqlc/oapi-codegen)

Revert edits to sqlc/oapi-codegen output; these should be regenerated
from the updated tasks.sql and OpenAPI schema.

* chore: drop oldestExcludingRetries description

* chore: gen

* chore: version

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Co-authored-by: mrkaye97 <mrkaye97@gmail.com>