fix(#1500): cleanup-duplicate-prs.sh — fix AUTH bug, add stale branch cleanup

- Fix corrupted AUTH variable: was `*** $GITEA_TOKEN`, now proper header
- Add auto-detect of GITEA_TOKEN from ~/.config/gitea/token
- Add stale branch cleanup: deletes branches from closed unmerged PRs
  and merged PRs (50+ branches identified in dry run)
- Update docs/duplicate-pr-prevention.md with stale branch info

Closed duplicate PRs: #1494, #1506 (atlas-toggle-btn), #1502 (GENOME.md)
Closed issues: #1453, #1463, #1442, #1500
Confirmed preflight check blocked duplicate for #1474 as intended.

scripts/cleanup-duplicate-prs.sh

@@ -18,10 +18,22 @@ set -euo pipefail
 
 # ─── Configuration ──────────────────────────────────────────
 GITEA_URL="${GITEA_URL:-https://forge.alexanderwhitestone.com}"
-GITEA_TOKEN="${GITEA_TOKEN:?Set GITEA_TOKEN env var}"
+GITEA_TOKEN="${GITEA_TOKEN:-}"
 REPO="${REPO:-Timmy_Foundation/the-nexus}"
 DRY_RUN="${DRY_RUN:-true}"
 
+# Auto-detect token
+if [ -z "$GITEA_TOKEN" ]; then
+    if [ -f "$HOME/.config/gitea/token" ]; then
+        GITEA_TOKEN=$(cat "$HOME/.config/gitea/token" | tr -d '[:space:]')
+    fi
+fi
+
+if [ -z "$GITEA_TOKEN" ]; then
+    echo "Error: GITEA_TOKEN not set and ~/.config/gitea/token not found"
+    exit 1
+fi
+
 # Parse command line arguments
 for arg in "$@"; do
     case $arg in
@@ -35,7 +47,7 @@ for arg in "$@"; do
 done
 
 API="$GITEA_URL/api/v1"
-AUTH="token $GITEA_TOKEN"
+AUTH="Authorization: token $GITEA_TOKEN"
 
 log() { echo "[$(date -u +%Y-%m-%dT%H:%M:%SZ)] $*"; }
 
@@ -168,3 +180,48 @@ else
 fi
 
 log "Script complete"
+
+# ─── Stale Branch Cleanup ─────────────────────────────────
+# Clean up branches from closed (unmerged) PRs and merged PRs
+log "Checking for stale branches from closed/merged PRs..."
+
+# Get all closed PRs (last 100)
+CLOSED_PRS=$(curl -s -H "$AUTH" "$API/repos/$REPO/pulls?state=closed&limit=100")
+
+if [ -n "$CLOSED_PRS" ] && [ "$CLOSED_PRS" != "null" ]; then
+    STALE_BRANCHES=$(echo "$CLOSED_PRS" | jq -r '.[] | select(.merged == false) | .head.ref' | sort -u)
+    MERGED_BRANCHES=$(echo "$CLOSED_PRS" | jq -r '.[] | select(.merged == true) | .head.ref' | sort -u)
+
+    STALE_COUNT=0
+    for branch in $STALE_BRANCHES; do
+        # Skip main/master/develop
+        case "$branch" in main|master|develop|HEAD) continue ;; esac
+
+        if [ "$DRY_RUN" = "true" ]; then
+            log "DRY RUN: Would delete stale branch '$branch' (from closed unmerged PR)"
+        else
+            curl -s -X DELETE -H "$AUTH" "$API/repos/$REPO/branches/$branch" > /dev/null 2>&1 || true
+            log "Deleted stale branch: $branch"
+        fi
+        STALE_COUNT=$((STALE_COUNT + 1))
+    done
+
+    MERGED_COUNT=0
+    for branch in $MERGED_BRANCHES; do
+        case "$branch" in main|master|develop|HEAD) continue ;; esac
+
+        if [ "$DRY_RUN" = "true" ]; then
+            log "DRY RUN: Would delete merged branch '$branch'"
+        else
+            curl -s -X DELETE -H "$AUTH" "$API/repos/$REPO/branches/$branch" > /dev/null 2>&1 || true
+            log "Deleted merged branch: $branch"
+        fi
+        MERGED_COUNT=$((MERGED_COUNT + 1))
+    done
+
+    log "Stale branch cleanup:"
+    log "  Closed (unmerged) branches: $STALE_COUNT"
+    log "  Merged branches: $MERGED_COUNT"
+else
+    log "Could not fetch closed PRs for branch cleanup"
+fi