feat(pydantic): add PYD-104 force_download rule (schema 15)

[Paramjeet-singh-neu]

Summary

• Add PYD-104 (medium / 0.8 / agent): FileUrl-family or WebFetchTool with force_download=True or "allow-local".
• Bump pack schema_version 14 → 15 for the new agent_file_url_force_download predicate (older binaries skip this rule and keep the rest).
• Fixture in the engine repo is identical. Companion engine PR: feat(pydantic): detect FileUrl and WebFetchTool force_download (PYD-104) trustabl#185

Test plan

• YAML matches trustabl testdata/rules-fixture/pydantic_ai/agent_safety.yaml
• Reviewer: confirm PYD-104 sits between PYD-103 and PYD-105 with no ID collision

Made with Cursor

[jhumel-code]

Thanks @Paramjeet-singh-neu. PYD-104 is unclaimed on main and no other open PR takes that ID, so it slots between PYD-103 and PYD-105 cleanly. The schema side checks out: every required field is present, pydantic_ai_agent is valid at agent scope, and the value: "True" / "allow-local" form matches how openai_sdk/approvals.yaml already uses agent_hosted_tool_kwarg_value (the evaluator quote strips string literals, so the allow-local arm compares correctly). The YAML is byte identical to the fixture in trustabl/trustabl#185, which adds the agent_file_url_force_download predicate and moves SupportedSchemaVersion to 15, so nothing here loads against a predicate the engine lacks. The explanation and fix are framed for Pydantic AI and name the concrete consequence rather than gesturing at it.

One change I want. Confidence 0.8 sits above PYD-103's 0.75, but PYD-103 reads a kwarg straight off the agent constructor, while the FileUrl arm here attributes a file level force_download to every Pydantic agent in that file. The looser attribution should carry the lower number, so please drop PYD-104 to 0.7 and mirror it in the engine fixture. This also cannot merge ahead of trustabl/trustabl#185, or rules-sync goes red and older binaries skip the rule.

PYD-104 will need a rationale doc in trustabl-rulebook before it ships. That part is on us and we are happy to pair on it.

Happy to take this once the confidence is adjusted.