Expose fact query max_rows cap

[justinjoy]

Summary

• Add optional fact schema registration max_rows support through HTTP, client API, and wyctl.
• Preserve the default 1000-row Datalog materialization cap while allowing explicit caps up to 1000000 rows.
• Reject out-of-range caps and keep executor-side clamping as defense in depth.
• Document max_rows behavior and add HTTP coverage for invalid caps, >1000 retrieval, request-limit truncation, and schema-cap truncation.

Closes #326

Review flow

• Architect and critic analysis identified the remaining issue as the fixed 1000 query cap; HTTP retract/forget already exists on main.
• Implementer produced atomic commit a95e5f9.
• Reviewer found unbounded max_rows risk.
• Follow-up commit 8015301 added the 1000000 server cap, policy validation, executor clamp, and cap tests.
• Final reviewer reported no findings.

Test

• git diff --check
• meson test -C builddir-facts daemon-http-facts --print-errorlogs
• meson test -C builddir-facts policy-store --print-errorlogs
• meson test -C builddir --print-errorlogs --suite wyrelog

Notes

• A full fact-enabled suite also surfaced existing unrelated local failures in fact-replay and fact-store; the changed HTTP/policy tests above pass, and the default CI-style suite passes locally.