feat: Add @mosaic/cli-tools package for git operations

New package providing CLI tools that work with both Gitea and GitHub:

Commands:
- mosaic-issue-{create,list,view,assign,edit,close,reopen,comment}
- mosaic-pr-{create,list,view,merge,review,close}
- mosaic-milestone-{create,list,close}

Features:
- Auto-detects platform (Gitea vs GitHub) from git remote
- Unified interface regardless of platform
- Available via `pnpm exec mosaic-*` in monorepo context

Updated docs/claude/orchestrator.md:
- Added CLI Tools section with usage examples
- Updated issue creation to use package commands

This makes Mosaic Stack fully self-contained for orchestration tooling.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/cli-tools/bin/milestone-close.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+# milestone-close.sh - Close a milestone on GitHub or Gitea
+# Usage: milestone-close.sh -t <title>
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/detect-platform.sh"
+
+# Parse arguments
+TITLE=""
+
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -t|--title)
+            TITLE="$2"
+            shift 2
+            ;;
+        -h|--help)
+            echo "Usage: milestone-close.sh -t <title>"
+            echo ""
+            echo "Options:"
+            echo "  -t, --title   Milestone title (required)"
+            echo "  -h, --help    Show this help"
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+if [[ -z "$TITLE" ]]; then
+    echo "Error: Milestone title is required (-t)"
+    exit 1
+fi
+
+detect_platform
+
+if [[ "$PLATFORM" == "github" ]]; then
+    gh api -X PATCH "/repos/{owner}/{repo}/milestones/$(gh api "/repos/{owner}/{repo}/milestones" --jq ".[] | select(.title==\"$TITLE\") | .number")" -f state=closed
+    echo "Closed GitHub milestone: $TITLE"
+elif [[ "$PLATFORM" == "gitea" ]]; then
+    tea milestone close "$TITLE"
+    echo "Closed Gitea milestone: $TITLE"
+else
+    echo "Error: Unknown platform"
+    exit 1
+fi