feat(templates): add budget tracking templates (Paperclip pattern)

Session 4 step 16 — post-hoc enforcement via PostToolUse hook with
PAUSED flag, budget-report.sh aggregates spend against window limit.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/templates/budget/budget-report.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+# Budget report: summarize cost events and compare against policy.
+# Bash 3.2 compatible. Uses python3 for aggregation.
+#
+# Usage: ./budget-report.sh
+#
+# Placeholders:
+#   {{WORKING_DIR}} - absolute path to project directory
+
+WORKING_DIR="{{WORKING_DIR}}"
+COST_LOG="$WORKING_DIR/budget/cost-events.jsonl"
+BUDGET_FILE="$WORKING_DIR/BUDGET.md"
+PAUSED_FLAG="$WORKING_DIR/budget/PAUSED"
+
+if [ ! -f "$COST_LOG" ]; then
+  echo "No cost events recorded yet."
+  exit 0
+fi
+
+COST_LOG="$COST_LOG" BUDGET_FILE="$BUDGET_FILE" PAUSED_FLAG="$PAUSED_FLAG" python3 -c "
+import json, re, os
+from collections import defaultdict
+
+cost_log = os.environ.get('COST_LOG', '')
+budget_file = os.environ.get('BUDGET_FILE', '')
+paused_flag = os.environ.get('PAUSED_FLAG', '')
+
+# Read events
+events = []
+with open(cost_log) as f:
+    for line in f:
+        line = line.strip()
+        if line:
+            try:
+                events.append(json.loads(line))
+            except:
+                pass
+
+# Aggregate
+by_agent = defaultdict(int)
+by_day = defaultdict(int)
+by_tool = defaultdict(int)
+
+for e in events:
+    agent = e.get('agent', 'unknown')
+    day = e.get('timestamp', '')[:10]
+    tool = e.get('tool_name', 'unknown')
+    by_agent[agent] += 1
+    by_day[day] += 1
+    by_tool[tool] += 1
+
+print('BUDGET REPORT')
+print('=' * 50)
+print('Total events: ' + str(len(events)))
+print()
+
+# Per-agent breakdown
+print('By Agent:')
+for agent, count in sorted(by_agent.items(), key=lambda x: -x[1]):
+    print('  ' + agent + ': ' + str(count) + ' events')
+print()
+
+# Per-day breakdown (last 7 days)
+print('By Day (last 7):')
+for day, count in sorted(by_day.items())[-7:]:
+    print('  ' + day + ': ' + str(count) + ' events')
+print()
+
+# Budget comparison
+if os.path.exists(budget_file):
+    content = open(budget_file).read()
+    limit_m = re.search(r'limit:\s*(\d+)\s*cents', content)
+    if limit_m:
+        limit = int(limit_m.group(1))
+        est_cents = len(events)  # rough proxy
+        pct = (est_cents / limit * 100) if limit > 0 else 0
+        print('Budget: ~' + str(est_cents) + '/' + str(limit) + ' cents (' + str(round(pct)) + '%)')
+
+# Paused status
+if os.path.exists(paused_flag):
+    print('')
+    print('!! AGENT PAUSED: ' + open(paused_flag).read().strip())
+    print('   Remove ' + paused_flag + ' to resume')
+"