Show Run results in notification email bodies

[JacobStephens2]

Summary

Put the Run result first in every Run notification body so it stays visible when a long issue title truncates the subject.

+Result:       merged
 Pull request: https://github.com/<owner>/<repo>/pull/<n>
 Session log:  <path>
 Command log:  <path>

Closes #572

Evidence

• Before: cargo test --test run_notification a_merge_run_sends_one_notification_that_it_merged -- --exact failed because the delivered email body started with Pull request: and contained no result.
  After: the same long-title regression passes with Result: merged at the start of the delivered body.
• Run notification integration tests: 20 passed. The existing delivered-email checks also cover ready for review, failed and interrupted outcomes.
• Shared formatter: 13 tests passed; Architect notification checks: 15 passed; Pickup notification checks: 9 passed; Spec notification checks: 6 passed.
• cargo test: 1,516 passed, 0 failed, 1 ignored. cargo check --all-targets, cargo fmt --check, and cargo clippy --all-targets -- -D warnings passed.

Test seams

• Run notification delivery: invoke the thirdshift CLI against real Git and the existing GitHub, Harness and Resend stand-ins; inspect the delivered email subject and plain-text body for Run, Spec run, Architect run and Pickup run outcomes.

Unaddressed findings

• Standards: none; 0 findings.
• Spec: none; 0 findings.

Both axes reviewed main...411cfc6 (main: ace41a0). Changed files left unread by review: none on either axis; both read all six changed files.

Merge Danger

Door: two-way

Reverting removes the added body line; there are no data or configuration changes.

Blast Radius: notifications

Run, Spec run, Architect run and Pickup run email bodies gain a leading result line.

Built with codex · gpt-6.1-sol · xhigh