chore: Resolve conflicts with main, update to v0.12.0

- sync.ts: add gemini + all targets, keep copilot, remove cursor (native), use shared hasPotentialSecrets
- install.ts + convert.ts: import both detectInstalledTools and resolveTargetOutputRoot; update --to all block to use new object API; fix resolvedScope ordering (was referencing target before definition)
- CHANGELOG.md: add v0.12.0 entry (auto-detect + Gemini sync)
- README.md: merge all install targets, collapsible output format table, sync defaults to --target all
- package.json: bump to 0.12.0
- sync --target now defaults to "all" when omitted

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@every-env/compound-plugin",
-  "version": "0.8.0",
+  "version": "0.12.0",
   "type": "module",
   "private": false,
   "bin": {