chore: project setup and tooling cleanup (#26)

* add project setup

* add tools to eslint

* remove contributing.md

* update claude md

* chore: simplify CI to single Node.js version (22)

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

* use node 20

* adjust formatting

* fix linting

* format

* fix layout

* fix: align CI node version to .nvmrc (22), remove redundant gotcha

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: arkon <arkon.85@hotmail.com>

.gitignore

@@ -41,6 +41,14 @@ Thumbs.db
 *.tmp
 *.temp
 
+# Generated output
+out/
+screenshots-echo-diag/
+tools/remotion/out/
+
+# Claude Code plan tracking
+plan.json
+
 # Unfinished TUI (local development only)
 src/tui/
 .claude/