chore: prepare pishoo v0.8.0-beta.4

[eareimu]

Summary

Prepare pishoo v0.8.0-beta.4 preview release.

Release surfaces

• Product/package release: pishoo v0.8.0-beta.4 preview channel
• Workspace packages: gateway v0.8.0-beta.4, pishoo v0.8.0-beta.4
• Package managers: DEB/RPM and Homebrew preview
• Sidecar package: pishoo-common v0.5.1-1 unchanged
• planned tag: v0.8.0-beta.4

Changes

• Keep identity access-rule databases as live policy sources.
• Evaluate gateway/pishoo access checks through the shared dhttp access policy evaluator trait.
• Enable the dhttp access ORM facade feature.
• Update release workflows to upload package assets from publish reports.

Verification

Previously run locally with temporary same-wave upstream patches:

• cargo +nightly fmt -- --check
• cargo test
• cargo clippy --all-targets --all-features -- -D warnings

Registry/package gates

• Requires same-wave upstream crates visible on crates.io before final lockfile convergence and merge/tag.
• Requires genmeta-xtask-release v0.2.0-beta.8 tag for release tooling.
• Release PR CI must cover the recent master RPM package failure.