fix: clean up update TUI output and suppress noisy stderr

- Add dedicated render branch for self_update results.
- Hide progress-only stderr on success to eliminate pipx noise.
- Remove generic "RESULT" heading from fallback key-value output.
- Bump version to 2.0.3.

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

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "coinhunter"
-version = "2.0.2"
+version = "2.0.3"
 description = "Binance-first trading CLI for balances, market data, opportunity scanning, and execution."
 readme = "README.md"
 license = {text = "MIT"}