chore: bump version and changelog (v0.8.3)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## [0.8.3] - 2026-03-19
+
+### Fixed
+
+- **Browse no longer navigates to dangerous URLs.** `goto`, `diff`, and `newtab` now block `file://`, `javascript:`, `data:` schemes and cloud metadata endpoints (`169.254.169.254`, `metadata.google.internal`). Localhost and private IPs are still allowed for local QA testing. (Closes #17)
+- **Setup script tells you what's missing.** Running `./setup` without `bun` installed now shows a clear error with install instructions instead of a cryptic "command not found." (Closes #147)
+- **`/debug` renamed to `/investigate`.** Claude Code has a built-in `/debug` command that shadowed the gstack skill. The systematic root-cause debugging workflow now lives at `/investigate`. (Closes #190)
+- **Shell injection surface removed.** All skill templates now use `source <(gstack-slug)` instead of `eval $(gstack-slug)`. Same behavior, no `eval`. (Closes #133)
+
+### Added
+
+- **25 new security tests.** URL validation (11 tests) and path traversal validation (14 tests) now have dedicated unit test suites covering scheme blocking, metadata IP blocking, directory escapes, and prefix collision edge cases.
+
 ## [0.8.2] - 2026-03-19
 
 ### Added

VERSION

@@ -1 +1 @@
-0.8.2
+0.8.3