chore: initialize monorepo with project scaffolding, configs, and CI setup

apps/blockchain-node/src/aitbc_chain/metrics.py

@@ -0,0 +1,40 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from threading import Lock
+from typing import Dict
+
+
+@dataclass
+class MetricValue:
+    name: str
+    value: float
+
+
+class MetricsRegistry:
+    def __init__(self) -> None:
+        self._counters: Dict[str, float] = {}
+        self._gauges: Dict[str, float] = {}
+        self._lock = Lock()
+
+    def increment(self, name: str, amount: float = 1.0) -> None:
+        with self._lock:
+            self._counters[name] = self._counters.get(name, 0.0) + amount
+
+    def set_gauge(self, name: str, value: float) -> None:
+        with self._lock:
+            self._gauges[name] = value
+
+    def render_prometheus(self) -> str:
+        with self._lock:
+            lines: list[str] = []
+            for name, value in sorted(self._counters.items()):
+                lines.append(f"# TYPE {name} counter")
+                lines.append(f"{name} {value}")
+            for name, value in sorted(self._gauges.items()):
+                lines.append(f"# TYPE {name} gauge")
+                lines.append(f"{name} {value}")
+            return "\n".join(lines) + "\n"
+
+
+metrics_registry = MetricsRegistry()