chore: bump version and changelog (v0.3.7)

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

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.3.7 — 2026-03-14
+
+### Added
+- **Screenshot element/region clipping** — `screenshot` command now supports element crop via CSS selector or @ref (`screenshot "#hero" out.png`, `screenshot @e3 out.png`), region clip (`screenshot --clip x,y,w,h out.png`), and viewport-only mode (`screenshot --viewport out.png`). Uses Playwright's native `locator.screenshot()` and `page.screenshot({ clip })`. Full page remains the default.
+- 10 new tests covering all screenshot modes (viewport, CSS, @ref, clip) and error paths (unknown flag, mutual exclusion, invalid coords, path validation, nonexistent selector).
+
 ## 0.3.6 — 2026-03-14
 
 ### Added

VERSION

@@ -1 +1 @@
-0.3.6
+0.3.7