restructure: move backend/ and layout/ into src/; convert README to org syntax; fix demo package conflict and alien-sap ioctl; update ROADMAP with v0.15.0; remove stale files

- Move backend/ and layout/ directories into src/
- Update all path references in ASD, scripts, docs
- Convert README.org from Markdown syntax to proper Org-mode
- Fix demo.lisp use-package conflict (both backend and input export #:read-event)
- Fix modern-backend TIOCGWINSZ ioctl alien type (alien-sap wrapper)
- Add v0.15.0 section to ROADMAP, update line count to 5760
- Add known gaps (suspend/resume-backend, slot modes) to v1.0.0 checklist
- Remove docs/plans/, debug-layout.lisp, system-index.txt, ci-watchdog.sh
- Move tangle.py to Hermes skill (org-babel-tangle)
- Add .gitignore for fasl files

scripts/verify-demo-pty.py

@@ -96,7 +96,7 @@ size = len(output)
 check("Output is non-empty", size > 100, f"got {size} bytes")
 check("Shows title 'cl-tty'", has_text(output, "cl-tty"))
 check("Shows component list", has_text(output, "TextInput"))
-check("Shows test count", has_text(output, "392"))
+check("Shows test count", has_text(output, "483"))
 check("Shows controls help", has_text(output, "Ctrl+C"))
 check("Shows tab bar items", has_text(output, "Home"))
 check("Shows Console tab", has_text(output, "Console"))