split: scrollbox-tabbar.org into scrollbox.org, tabbar.org, container-package.org

- Create org/scrollbox.org (tangles scrollbox.lisp)
- Create org/tabbar.org (tangles tabbar.lisp)
- Create org/container-package.org (tangles container-package.lisp)
- Disable :tangle in old scrollbox-tabbar.org (kept for prose docs)
- Fix missing paren in render method (was depth=1 at EOF)
- All 483 tests pass, 14 suites, 100%

org/tabbar.org

@@ -0,0 +1,60 @@
+#+TITLE: TabBar
+#+STARTUP: content
+#+FILETAGS: :cl-tty:container:
+
+* Overview
+
+TabBar handles horizontal tab navigation with keyboard support.
+Tabs are rendered as labeled items; the active tab is highlighted.
+
+* Implementation
+
+#+BEGIN_SRC lisp :tangle ../src/components/tabbar.lisp
+(in-package #:cl-tty.container)
+
+(defclass tab-bar (dirty-mixin)
+  ((tabs :initform nil :initarg :tabs :accessor tab-bar-tabs :type list)
+   (active :initform nil :initarg :active :accessor tab-bar-active)
+   (layout-node :initform (make-layout-node) :accessor tab-bar-layout-node)
+   (focusable :initform t :accessor tab-bar-focusable)))
+
+(defun make-tab-bar (&key tabs active)
+  (make-instance 'tab-bar :tabs (or tabs nil) :active active))
+
+(defun tab-bar-add (tb id title)
+  (setf (tab-bar-tabs tb) (nconc (tab-bar-tabs tb) (list (list :id id :title title))))
+  (unless (tab-bar-active tb) (setf (tab-bar-active tb) id)) id)
+
+(defmethod component-layout-node ((tb tab-bar)) (tab-bar-layout-node tb))
+
+(defun tab-bar-next (tb)
+  (let* ((tabs (tab-bar-tabs tb)) (current (tab-bar-active tb))
+         (ids (mapcar (lambda (tab) (getf tab :id)) tabs)) (pos (position current ids)))
+    (when pos (let ((next (nth (mod (1+ pos) (length ids)) ids)))
+                (setf (tab-bar-active tb) next) (mark-dirty tb)))))
+
+(defun tab-bar-prev (tb)
+  (let* ((tabs (tab-bar-tabs tb)) (current (tab-bar-active tb))
+         (ids (mapcar (lambda (tab) (getf tab :id)) tabs)) (pos (position current ids)))
+    (when pos (let ((prev (nth (mod (1- pos) (length ids)) ids)))
+                (setf (tab-bar-active tb) prev) (mark-dirty tb)))))
+
+(defun tab-bar-select (tb id) (setf (tab-bar-active tb) id) (mark-dirty tb))
+
+(defun tab-bar-handle-key (tb event)
+  (case (key-event-key event) (:left (tab-bar-prev tb) t) (:right (tab-bar-next tb) t) (t nil)))
+
+(defmethod render ((tb tab-bar) backend)
+  (let* ((ln (tab-bar-layout-node tb)) (x (if ln (layout-node-x ln) 0))
+         (y (if ln (layout-node-y ln) 0)) (w (if ln (layout-node-width ln) 80))
+         (active-id (tab-bar-active tb)) (tabs (tab-bar-tabs tb)) (x-pos x))
+    (dolist (tab tabs)
+      (let* ((id (getf tab :id)) (title (getf tab :title))
+             (label (format nil " ~A " title)) (label-len (length label))
+             (is-active (eql id active-id))
+             (fg (if is-active :accent :text-muted))
+             (bg (if is-active :background-element nil)))
+        (when (>= (+ x-pos label-len 2) w) (draw-text backend x-pos y "..." :text-muted nil) (return))
+        (draw-text backend x-pos y label fg bg) (incf x-pos (+ label-len 2)))))
+  (values))
+#+END_SRC