feat(artifacts): capture short PR refs + harvest merged PR by commit

Two refinements to the close-time ledger:
- artifact extractor now reads "PR #51" / "PR#51" / "pull request #51" from
  event text (normalised to "PR #51"), anchored to the PR keyword so a bare
  "#3" in prose is not captured.
- harvest falls back to GitHub commit search (gh pr list --search <HEAD-sha>
  --state merged) when the branch's open PR is gone — the common case of
  closing a task on main after the branch was deleted. Best-effort.

Bump 0.26.6.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Shahinyanm

CHANGELOG.md

@@ -7,6 +7,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.26.6] - 2026-06-17
+
+### Added
+- **Short PR references are captured too.** The artifact extractor now reads
+  `PR #51` / `PR#51` / `pull request #51` from event text (normalised to
+  `PR #51`), not just full `/pull/N` URLs — anchored to the PR keyword so a
+  bare `#3` in prose is not mistaken for a PR.
+- **Close harvest finds the merged PR even after the branch is gone.** When a
+  task is closed on `main` (the branch already deleted, so `gh pr view` finds
+  nothing), the harvest falls back to GitHub commit search
+  (`gh pr list --search <HEAD-sha> --state merged`) to recover the PR that
+  introduced the current commit. Still best-effort — no `gh`/match just yields
+  no PR.
+
 ## [0.26.5] - 2026-06-17
 
 ### Added

Cargo.lock

@@ -7,7 +7,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.26.5"
+version = "0.26.6"
 edition = "2021"
 rust-version = "1.88"
 license = "MIT"

Cargo.toml

@@ -86,6 +86,18 @@ pub fn extract(text: &str) -> Artifacts {
         text,
     );
 
+    // Short PR references: "PR #51", "PR#51", "pull request #51". Anchored to
+    // the PR / "pull request" keyword so a bare "#3" in prose (step #3, issue
+    // #3) is NOT captured. Normalised to "PR #<n>" so it dedupes cleanly and
+    // renders next to full URLs under the same `PRs:` group.
+    if let Ok(re) = Regex::new(r"(?i)\b(?:PR|pull request)\s*#(\d+)\b") {
+        for cap in re.captures_iter(text) {
+            if let Some(m) = cap.get(1) {
+                a.pr_urls.push(format!("PR #{}", m.as_str()));
+            }
+        }
+    }
+
     // Ticket IDs: ABC-123. At least 2 letters to avoid matching version
     // strings like v1-2 and minimum 1 digit.
     static_re(
@@ -240,6 +252,15 @@ mod tests {
         assert!(a.is_empty());
     }
 
+    #[test]
+    fn captures_short_pr_reference_but_not_bare_hash() {
+        let a = extract("merged PR #51 and PR#52, see pull request #53");
+        assert_eq!(a.pr_urls, vec!["PR #51", "PR #52", "PR #53"]);
+        // bare hashes in prose must NOT be captured as PRs
+        let b = extract("step #3 of 5, issue #7, line #42");
+        assert!(b.pr_urls.is_empty(), "got: {:?}", b.pr_urls);
+    }
+
     #[test]
     fn json_round_trip() {
         let a = Artifacts {

crates/tj-core/src/artifacts.rs

@@ -49,7 +49,13 @@ pub fn build(branch: Option<String>, commit: Option<String>, pr_url: Option<Stri
 pub fn harvest(dir: &Path) -> Artifacts {
     let branch = git(dir, &["rev-parse", "--abbrev-ref", "HEAD"]);
     let commit = git(dir, &["rev-parse", "--short", "HEAD"]);
-    let pr_url = gh_pr_url(dir);
+    // PR resolution, best-effort and in order of reliability:
+    //   1. the open PR for the current branch (pre-merge close), else
+    //   2. the merged PR that contains HEAD (post-merge close, branch gone).
+    // The second covers the common case where the task is closed on `main`
+    // after the branch was deleted, so `gh pr view` finds nothing.
+    let pr_url = gh_pr_url(dir)
+        .or_else(|| git(dir, &["rev-parse", "HEAD"]).and_then(|sha| gh_pr_for_commit(dir, &sha)));
     build(branch, commit, pr_url)
 }
 
@@ -94,6 +100,29 @@ fn gh_pr_url(dir: &Path) -> Option<String> {
     }
 }
 
+/// Best-effort URL of the merged PR that introduced `sha`, via GitHub's commit
+/// search. Used as a fallback when the branch's open PR is gone (task closed on
+/// `main` after the branch was deleted). `None` on any failure.
+fn gh_pr_for_commit(dir: &Path, sha: &str) -> Option<String> {
+    let out = Command::new("gh")
+        .args([
+            "pr", "list", "--state", "merged", "--search", sha, "--limit", "1", "--json", "url",
+            "-q", ".[0].url",
+        ])
+        .current_dir(dir)
+        .output()
+        .ok()?;
+    if !out.status.success() {
+        return None;
+    }
+    let s = String::from_utf8_lossy(&out.stdout).trim().to_string();
+    if s.starts_with("http") {
+        Some(s)
+    } else {
+        None
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;