feat: add self-update command and bump to 2.0.1

- Add `coinhunter update` CLI command for pipx/pip upgrade
- README: document update behavior and recommend pipx install
- Dynamic version badge with cacheSeconds=60
- Version bump: 2.0.0 → 2.0.1

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

src/coinhunter/__init__.py

@@ -1,3 +1,8 @@
 """CoinHunter V2."""
 
-__version__ = "2.0.0"
+try:
+    from importlib.metadata import version
+
+    __version__ = version("coinhunter")
+except Exception:  # pragma: no cover
+    __version__ = "unknown"

src/coinhunter/cli.py

@@ -10,7 +10,7 @@ from . import __version__
 from .binance.spot_client import SpotBinanceClient
 from .binance.um_futures_client import UMFuturesClient
 from .config import ensure_init_files, get_binance_credentials, load_config
-from .runtime import get_runtime_paths, print_json
+from .runtime import get_runtime_paths, print_json, self_update
 from .services import account_service, market_service, opportunity_service, trade_service
 
 
@@ -102,6 +102,8 @@ def build_parser() -> argparse.ArgumentParser:
     scan_parser = opportunity_subparsers.add_parser("scan")
     scan_parser.add_argument("--symbols", nargs="*")
 
+    subparsers.add_parser("update", help="Upgrade coinhunter to the latest version")
+
     return parser
 
 
@@ -231,6 +233,10 @@ def main(argv: list[str] | None = None) -> int:
                 return 0
             parser.error("opportunity requires `portfolio` or `scan`")
 
+        if args.command == "update":
+            print_json(self_update())
+            return 0
+
         parser.error(f"Unsupported command {args.command}")
         return 2
     except Exception as exc:

src/coinhunter/runtime.py

@@ -4,6 +4,9 @@ from __future__ import annotations
 
 import json
 import os
+import shutil
+import subprocess
+import sys
 from dataclasses import asdict, dataclass, is_dataclass
 from datetime import date, datetime
 from pathlib import Path
@@ -50,3 +53,17 @@ def json_default(value: Any) -> Any:
 
 def print_json(payload: Any) -> None:
     print(json.dumps(payload, ensure_ascii=False, indent=2, sort_keys=True, default=json_default))
+
+
+def self_update() -> dict[str, Any]:
+    if shutil.which("pipx"):
+        cmd = ["pipx", "upgrade", "coinhunter"]
+    else:
+        cmd = [sys.executable, "-m", "pip", "install", "--upgrade", "coinhunter"]
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    return {
+        "command": " ".join(cmd),
+        "returncode": result.returncode,
+        "stdout": result.stdout.strip(),
+        "stderr": result.stderr.strip(),
+    }