fix(mirror): Step 0b self-heals stuck submitted_by via cron retry

Step 4.5's submitted_by write inherits the same one-shot failure mode
that Phase 1's Step 0 sweep was designed to retire. On transient
GitHub API failure, link-only fallback writes github_pr and permanently
closes the retry window — submitted_by stays stuck on 'm3taversal'
(bot identity), and contribution_events never gets the author event.

Step 0b adds a second sweep alongside Step 0:
  SELECT ... WHERE github_pr IS NOT NULL
              AND (submitted_by IS NULL OR submitted_by = 'm3taversal')

Same idempotent cron-retry shape: SELECT empty when clean, per-row
GitHub API call + UPDATE only when stuck. Targets bidirectional
repos only (gh-pr-* branches don't exist for main_only mirrors).

Derives bidirectional GitHub repo from MIRROR_REPOS at sweep time
since Step 0 runs before sync_repo() sets GITHUB_REPO scope.

Doubles as future-proof safety net: any external PR landing during
the deploy window with submitted_by stuck on bot identity gets
self-healed on the next cron tick. No backfill script needed.

Per Ganymede line-level review of 1decf09.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/sync-mirror.sh

@@ -275,9 +275,26 @@ print('no')
         fi
         log "Auto-created PR #$PR_NUM on Forgejo for $branch"
 
-        # Step 4.5: Link GitHub PR to Forgejo PR in pipeline DB
+        # Step 4.5: Link GitHub PR to Forgejo PR + populate submitted_by from GitHub user.login.
+        #
+        # Why submitted_by here: sync-mirror creates the Forgejo PR using the admin
+        # token (user=m3taversal), so the Forgejo PR's submitter is bot-identity, not
+        # the GitHub author (FwazB, etc). Without this fix, contribution_events emits
+        # zero author events for external PRs because record_contributor_attribution
+        # treats m3taversal as a bot and finds no other signal. Architectural fix per
+        # Ship + Cory after the FwazB PR #4066 attribution gap (Apr 28).
+        local GH_USER
+        GH_USER=""
         if [[ "$branch" == gh-pr-* ]]; then
             GH_PR_NUM=$(echo "$branch" | sed 's|gh-pr-\([0-9]*\)/.*|\1|')
+            # Look up GitHub PR author for submitted_by attribution.
+            local PAT_GHU
+            PAT_GHU=$(cat "$GITHUB_PAT_FILE" 2>/dev/null | tr -d '[:space:]')
+            if [ -n "$PAT_GHU" ] && [[ "$GH_PR_NUM" =~ ^[0-9]+$ ]]; then
+                GH_USER=$(curl -sf "https://api.github.com/repos/$GITHUB_REPO/pulls/$GH_PR_NUM" \
+                    -H "Authorization: token $PAT_GHU" 2>/dev/null | \
+                    python3 -c "import sys,json; print((json.load(sys.stdin).get('user') or {}).get('login',''))" 2>/dev/null || true)
+            fi
         else
             local PAT
             PAT=$(cat "$GITHUB_PAT_FILE" 2>/dev/null | tr -d '[:space:]')
@@ -289,9 +306,24 @@ print('no')
             fi
         fi
         if [[ "$GH_PR_NUM" =~ ^[0-9]+$ ]] && [[ "$PR_NUM" =~ ^[0-9]+$ ]]; then
-            sqlite3 "$PIPELINE_DB" "UPDATE prs SET github_pr = $GH_PR_NUM, source_channel = 'github' WHERE number = $PR_NUM;" 2>/dev/null && \
+            # GitHub usernames: 1-39 chars, alphanumeric + hyphen, can't start/end with hyphen.
-                log "Linked GitHub PR #$GH_PR_NUM -> Forgejo PR #$PR_NUM" || \
+            # Strict regex is the SQL-injection safety boundary (no bash sqlite3 parametric binding).
-                log "WARN: Failed to link GitHub PR #$GH_PR_NUM to Forgejo PR #$PR_NUM in DB"
+            if [[ "$GH_USER" =~ ^[a-zA-Z0-9]([a-zA-Z0-9-]{0,37}[a-zA-Z0-9])?$ ]]; then
+                # Lowercase for canonical handle storage (matches contributor.py normalize)
+                local GH_USER_LC
+                GH_USER_LC=$(echo "$GH_USER" | tr '[:upper:]' '[:lower:]')
+                sqlite3 "$PIPELINE_DB" "UPDATE prs SET github_pr = $GH_PR_NUM, source_channel = 'github', submitted_by = '$GH_USER_LC' WHERE number = $PR_NUM;" 2>/dev/null && \
+                    log "Linked GitHub PR #$GH_PR_NUM -> Forgejo PR #$PR_NUM (author: $GH_USER_LC)" || \
+                    log "WARN: Failed to link GitHub PR #$GH_PR_NUM to Forgejo PR #$PR_NUM in DB"
+            else
+                # Fall back to link-only when user.login lookup failed or was malformed.
+                # Still better than no link; record_contributor_attribution can use
+                # other signals (commit author trailer, etc) — author event may still
+                # not emit, but submitted_by stays NULL/whatever discovery set.
+                sqlite3 "$PIPELINE_DB" "UPDATE prs SET github_pr = $GH_PR_NUM, source_channel = 'github' WHERE number = $PR_NUM;" 2>/dev/null && \
+                    log "Linked GitHub PR #$GH_PR_NUM -> Forgejo PR #$PR_NUM (author lookup failed)" || \
+                    log "WARN: Failed to link GitHub PR #$GH_PR_NUM to Forgejo PR #$PR_NUM in DB"
+            fi
         fi
     done
 }
@@ -393,6 +425,50 @@ if [ -f "$PIPELINE_DB" ]; then
             log "self-heal: linked Forgejo PR #$pr_num -> GitHub PR #$gh_pr_num"
         fi
     done
+
+    # Step 0b: self-heal stuck submitted_by on linked gh-pr-* PRs.
+    # Step 4.5 fall-through writes github_pr but leaves submitted_by as 'm3taversal'
+    # (bot identity) on transient GitHub API failures. Without retry, contribution_events
+    # never gets the author event — same one-shot failure mode Step 0 was designed to
+    # retire. Same idempotent cron-retry shape: SELECT empty when clean, per-row API
+    # call only when stuck. Targets bidirectional repos only (gh-pr-* branches don't
+    # exist for main_only mirrors).
+    GH_REPO_BIDIR=""
+    for entry in "${MIRROR_REPOS[@]}"; do
+        read -r _f gh_repo _bare mode <<< "$entry"
+        if [ "$mode" = "bidirectional" ]; then
+            GH_REPO_BIDIR="$gh_repo"
+            break
+        fi
+    done
+    if [ -n "$GH_REPO_BIDIR" ] && [ -f "$GITHUB_PAT_FILE" ]; then
+        sqlite3 -separator '|' "$PIPELINE_DB" \
+            "SELECT number, branch FROM prs
+             WHERE branch LIKE 'gh-pr-%'
+               AND github_pr IS NOT NULL
+               AND (submitted_by IS NULL OR submitted_by = 'm3taversal');" \
+            2>/dev/null | while IFS='|' read -r pr_num branch; do
+            gh_pr_num=$(echo "$branch" | sed -n 's|^gh-pr-\([0-9][0-9]*\)/.*|\1|p')
+            [ -z "$gh_pr_num" ] && continue
+            PAT_S0=$(cat "$GITHUB_PAT_FILE" 2>/dev/null | tr -d '[:space:]')
+            [ -z "$PAT_S0" ] && continue
+            gh_user=$(curl -sf "https://api.github.com/repos/$GH_REPO_BIDIR/pulls/$gh_pr_num" \
+                -H "Authorization: token $PAT_S0" 2>/dev/null | \
+                python3 -c "import sys,json; print((json.load(sys.stdin).get('user') or {}).get('login',''))" 2>/dev/null || true)
+            # Regex matches Step 4.5: GitHub username spec (anchored, alnum + hyphen,
+            # no consecutive-hyphen check). SQL-injection boundary: char class excludes
+            # quotes/semicolons/backslashes, so single-quoted literal is safe.
+            if [[ "$gh_user" =~ ^[a-zA-Z0-9]([a-zA-Z0-9-]{0,37}[a-zA-Z0-9])?$ ]]; then
+                gh_user_lc=$(echo "$gh_user" | tr '[:upper:]' '[:lower:]')
+                # SQL-integer-safe: pr_num from INTEGER column, gh_user_lc regex-validated.
+                if sqlite3 "$PIPELINE_DB" \
+                    "UPDATE prs SET submitted_by = '$gh_user_lc' WHERE number = $pr_num;" \
+                    2>/dev/null; then
+                    log "self-heal: set submitted_by=$gh_user_lc on Forgejo PR #$pr_num (GitHub PR #$gh_pr_num)"
+                fi
+            fi
+        done
+    fi
 fi
 
 for entry in "${MIRROR_REPOS[@]}"; do