Add session eject feature and terminal UX improvements

- Add eject button for tmux sessions (keeps tmux running, removes from Spiceflow)
- Add refresh button to session settings for all providers
- Improve terminal controls: larger buttons, more zoom levels (50-150%), copy selection, paste clipboard, enter key
- Fix session navigation: properly reload when switching between sessions
- Update tmux screen presets to larger dimensions (fullscreen 260x48, desktop 120x48, landscape 80x24)
- Add testing documentation to CLAUDE.md
- Refactor E2E tests to use API-based cleanup

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -123,6 +123,59 @@ Environment variables or `server/resources/config.edn`:
 | `CLAUDE_SESSIONS_DIR` | ~/.claude/projects | Claude sessions |
 | `OPENCODE_CMD` | opencode | OpenCode binary |
 
+## Testing Changes
+
+Always test changes before considering them complete. Choose the appropriate testing method:
+
+### 1. E2E Tests (Playwright)
+For UI changes, user flows, and integration between frontend/backend:
+```bash
+cd e2e && npm test                    # Run all E2E tests
+cd e2e && npm run test:headed         # Visible browser for debugging
+cd e2e && npm test -- -g "test name"  # Run specific test
+```
+
+### 2. Unit Tests (Clojure)
+For backend logic, pure functions, and isolated components:
+```bash
+cd server && clj -M:test              # Run all unit tests
+```
+
+### 3. REPL Testing
+For quick one-off validation of Clojure code during development:
+```clojure
+;; In REPL (clj -M:dev, then (go))
+(require '[spiceflow.some-ns :as ns])
+(ns/some-function arg1 arg2)          ; Test function directly
+```
+
+### 4. Manual API Testing
+For testing HTTP endpoints directly:
+```bash
+# Health check
+curl http://localhost:3000/api/health
+
+# List sessions
+curl http://localhost:3000/api/sessions
+
+# Create session
+curl -X POST http://localhost:3000/api/sessions \
+  -H "Content-Type: application/json" \
+  -d '{"provider": "claude"}'
+
+# Get session
+curl http://localhost:3000/api/sessions/:id
+```
+
+### When to Use Each
+| Change Type | Recommended Testing |
+|-------------|---------------------|
+| UI component | E2E tests |
+| API endpoint | Manual API + unit tests |
+| Business logic | Unit tests + REPL |
+| User flow | E2E tests |
+| Bug fix | Add regression test + manual verify |
+
 ## Subdirectory CLAUDE.md Files
 
 Each directory has specific details: