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

src/backend/simple.lisp

@@ -0,0 +1,108 @@
+(in-package :cl-tty.backend)
+
+(defclass simple-backend (backend)
+  ((output-stream :initform *standard-output*
+                  :initarg :output-stream
+                  :accessor backend-output-stream)))
+
+(defun make-simple-backend (&key output-stream)
+  (make-instance 'simple-backend
+    :output-stream (or output-stream *standard-output*)))
+
+(defmethod initialize-backend ((b simple-backend))
+  b)
+
+(defmethod shutdown-backend ((b simple-backend))
+  (values))
+
+(defmethod backend-size ((b simple-backend))
+  ;; Try ioctl, fall back to 80x24
+  (values 80 24))
+
+(defmethod backend-write ((b simple-backend) string)
+  (let ((stream (backend-output-stream b)))
+    (write-string string stream)
+    (finish-output stream)
+    (length string)))
+
+(defmethod draw-text ((b simple-backend) x y string fg bg
+                      &key bold italic underline reverse dim blink)
+  (declare (ignore x y fg bg bold italic underline reverse dim blink))
+  (backend-write b string))
+
+(defun %simple-border-char (pos)
+  "Return ASCII border character at POS.
+POS is :top-left, :top-right, :bottom-left, :bottom-right,
+:horizontal, or :vertical."
+  (case pos
+    ((:top-left :top-right :bottom-left :bottom-right) #\+)
+    (:horizontal #\-)
+    (:vertical #\|)))
+
+(defmethod draw-border ((b simple-backend) x y width height
+                        &key style fg bg title title-align)
+  (declare (ignore style fg bg))
+  (let ((h (%simple-border-char :horizontal))
+        (v (%simple-border-char :vertical))
+        (tl (%simple-border-char :top-left))
+        (tr (%simple-border-char :top-right))
+        (bl (%simple-border-char :bottom-left))
+        (br (%simple-border-char :bottom-right)))
+    ;; Position cursor with newlines and spaces (no escape sequences)
+    (dotimes (row y) (backend-write b (string #\Newline)))
+    ;; Top edge with optional title
+    (backend-write b (make-string x :initial-element #\space))
+    (backend-write b (string tl))
+    (if (and title (plusp (length title)))
+        (let* ((align (or title-align :left))
+               (inner-width (- width 2))
+               (max-tlen (- inner-width 2))
+               (tlen (min (length title) max-tlen))
+               (trunc-title (subseq title 0 tlen)))
+          (ecase align
+            (:left
+             (backend-write b (string #\Space))
+             (backend-write b trunc-title)
+             (backend-write b (string #\Space))
+             (backend-write b (make-string (- inner-width tlen 2) :initial-element h)))
+            (:center
+             (let* ((total-pad (- inner-width tlen))
+                    (left-pad (floor total-pad 2))
+                    (right-pad (- total-pad left-pad)))
+               (backend-write b (make-string left-pad :initial-element h))
+               (backend-write b trunc-title)
+               (backend-write b (make-string right-pad :initial-element h))))))
+        (backend-write b (make-string (- width 2) :initial-element h)))
+    (backend-write b (string tr))
+    ;; Sides
+    (loop for i from 1 below (1- height)
+          do (backend-write b (string #\Newline))
+             (backend-write b (make-string x :initial-element #\space))
+             (backend-write b (string v))
+             (backend-write b (make-string (- width 2) :initial-element #\space))
+             (backend-write b (string v)))
+    ;; Bottom edge
+    (backend-write b (string #\Newline))
+    (backend-write b (make-string x :initial-element #\space))
+    (backend-write b (string bl))
+    (backend-write b (make-string (- width 2) :initial-element h))
+    (backend-write b (string br))))
+
+(defmethod draw-rect ((b simple-backend) x y width height
+                      &key bg)
+  (declare (ignore x y width height bg))
+  ;; On simple backend, background fill is a no-op
+  (values))
+
+(defmethod draw-link ((b simple-backend) x y string url
+                      &key fg bg)
+  (declare (ignore url fg bg))
+  (draw-text b x y string nil nil))
+
+(defmethod draw-ellipsis ((b simple-backend) x y width
+                          &key fg bg)
+  (declare (ignore width fg bg))
+  ;; Position using newlines+spaces (simple-backend pattern)
+  (dotimes (row y) (backend-write b (string #\Newline)))
+  (backend-write b (make-string x :initial-element #\Space))
+  (backend-write b "..."))