feat: Add forge cleanup tools and documentation (#1128)

## Summary
Implements forge cleanup tools and documentation as requested in issue #1128.

## Changes
- scripts/cleanup-duplicate-prs.sh: Automated duplicate PR detection
- docs/forge-cleanup-analysis.md: Analysis of duplicate PRs
- docs/forge-cleanup-report.md: Cleanup report with metrics
- .github/workflows/pr-duplicate-check.yml: Weekly automated checks

Issue: #1128

scripts/README.md

@@ -0,0 +1,86 @@
+# Scripts
+
+## cleanup-duplicate-prs.sh
+
+Automated detection and cleanup of duplicate open PRs.
+
+### Purpose
+
+This script identifies PRs that are duplicates (same issue number or very similar titles) and closes the older ones. It's designed to help maintain a clean PR board and prevent confusion from duplicate work.
+
+### Features
+
+- **Issue-based grouping**: Groups PRs by issue number extracted from titles
+- **Date-based selection**: Keeps the newest PR, closes older duplicates
+- **Dry-run mode**: Shows what would be done without making changes
+- **Stale PR detection**: Identifies PRs older than 30 days with no activity
+- **Explanatory comments**: Adds comments when closing PRs to explain why
+
+### Usage
+
+```bash
+# Dry run (default) - shows what would be done
+./scripts/cleanup-duplicate-prs.sh
+
+# Actually close duplicates
+./scripts/cleanup-duplicate-prs.sh --close
+
+# Set environment variables
+export GITEA_TOKEN="your_token_here"
+export REPO="Timmy_Foundation/the-nexus"
+export GITEA_URL="https://forge.alexanderwhitestone.com"
+```
+
+### Configuration
+
+The script uses the following environment variables:
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `GITEA_TOKEN` | (required) | Gitea API token with repo access |
+| `GITEA_URL` | `https://forge.alexanderwhitestone.com` | Gitea instance URL |
+| `REPO` | `Timmy_Foundation/the-nexus` | Repository in `owner/repo` format |
+| `DRY_RUN` | `true` | Set to `false` to actually close PRs |
+
+### How It Works
+
+1. **Fetch open PRs**: Gets all open PRs from the repository
+2. **Extract issue numbers**: Parses issue numbers from PR titles (e.g., `#123`)
+3. **Group by issue**: Groups PRs that address the same issue
+4. **Identify duplicates**: Finds issues with multiple open PRs
+5. **Select newest**: For each duplicate group, keeps the newest PR
+6. **Close older PRs**: Closes older duplicates with explanatory comments
+7. **Check for stale PRs**: Identifies PRs older than 30 days
+
+### Example Output
+
+```
+[2026-04-14T00:57:05Z] Checking open PRs for Timmy_Foundation/the-nexus (dry_run: true)
+[2026-04-14T00:57:17Z] Found 14 open PRs
+[2026-04-14T00:57:17Z] Issue #1338 has 2 open PRs
+[2026-04-14T00:57:17Z] Keeping PR #1392 (newest)
+[2026-04-14T00:57:17Z] DRY RUN: Would close PR #1388
+[2026-04-14T00:57:17Z] Issue #1354 has 2 open PRs
+[2026-04-14T00:57:17Z] Keeping PR #1391 (newest)
+[2026-04-14T00:57:17Z] DRY RUN: Would close PR #1384
+[2026-04-14T00:57:17Z] Cleanup complete:
+[2026-04-14T00:57:17Z]   Duplicate issue groups found: 4
+[2026-04-14T00:57:17Z]   PRs closed: 0
+[2026-04-14T00:57:17Z]   Dry run: true
+```
+
+### Safety Features
+
+- **Dry-run by default**: Won't close PRs unless explicitly told to
+- **Explanatory comments**: Adds comments before closing to explain why
+- **Newest PR preserved**: Always keeps the most recent PR for each issue
+- **No force deletion**: Only closes PRs, doesn't delete branches
+
+### Integration
+
+This script can be integrated into CI/CD pipelines or run manually as part of regular maintenance. It's designed to be run weekly to keep the PR board clean.
+
+### Related Issues
+
+- **Issue #1128**: Forge Cleanup — PRs Closed, Milestones Deduplicated, Policy Issues Filed
+- **Issue #1127**: Evening triage pass (predecessor to #1128)