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/audit-compiler.lisp

@@ -26,9 +26,9 @@
               *results*)))))
 
 (let ((files
-        '("backend/classes.lisp" "backend/package.lisp"
-          "backend/detection.lisp" "backend/simple.lisp" "backend/modern.lisp"
-          "layout/layout.lisp"
+        '("src/backend/classes.lisp" "src/backend/package.lisp"
+          "src/backend/detection.lisp" "src/backend/simple.lisp" "src/backend/modern.lisp"
+          "src/layout/layout.lisp"
           "src/components/container-package.lisp"
           "src/components/dialog-package.lisp" "src/components/dialog.lisp"
           "src/components/dirty.lisp"
@@ -45,8 +45,8 @@
           "src/components/box.lisp"
           "src/rendering/framebuffer.lisp"
           "demo.lisp"
-          "backend/modern-tests.lisp" "backend/tests.lisp"
-          "layout/tests.lisp"
+          "src/backend/modern-tests.lisp" "src/backend/tests.lisp"
+          "src/layout/tests.lisp"
           "src/components/box-tests.lisp" "src/components/dirty-tests.lisp"
           "src/components/render-tests.lisp" "src/components/theme-tests.lisp"
           "src/components/input-tests.lisp"