Record hosted workflow evidence

[willamhou]

Records the hosted GitHub workflow evidence from PR #10/#11/#12 and turns the exact hosted patch request shape into a default benchmark regression.

Changes:

• Add a pr_workflow benchmark case for the exact @deepseek patch change ... becomes ... request shape used by the hosted write smoke.
• Update the benchmark manifest regression test from 25 to 26 pr_workflow cases.
• Update current status and the GitHub Action bridge spec now that hosted write proof exists and temporary fixtures were removed.
• Note that the temporary evidence branches were cleaned up.

Validation:

• cargo fmt --check
• git diff --check
• cargo test default_manifest_includes_github_action_bridge_pr_workflow_cases --lib
• cargo run --quiet -- benchmark --case fixture-github-action-patch-trigger-exact-replacement-rust-mini --out /tmp/deepseek-hosted-exact-patch-benchmark.md
• cargo test --lib -- --test-threads=1

[github-actions]

DeepSeekCode review of PR #13 (Record hosted workflow evidence)

Let me fetch the actual PR diff from GitHub since there's no local diff available.