fix: revert oapi to v2.6.0

[archandatta]

Note

Medium Risk
Regenerates large portions of lib/oapi/oapi.go, including request parameter encoding and server parameter binding helpers, which could subtly change runtime behavior. Main risk is mismatched query/path parsing or validation differences after the codegen upgrade.

Overview
Regenerates lib/oapi/oapi.go with oapi-codegen v2.6.0, updating the embedded swagger payload, adding Valid() helpers for multiple enums, and switching generated request/handler parameter styling/binding to the newer runtime.*WithOptions APIs (with explicit Type/Format, e.g. UUIDs and booleans).

Simplifies the oapi-generate Makefile target by dropping the patch_strict_optional_json step and deletes scripts/oapi/patch_strict_optional_json, leaving only the SSE methods patch as a post-processing step.

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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