Subagent review fixes: textarea ignore-w, hit-test recursion, select/tabbar position, X10 release, CSI param < digit, text-input truncation

CRITICAL: Remove (declare (ignore w)) from textarea render (textarea.lisp:251)
  w is used for horizontal truncation on the next line.  Declaring it
  ignored while using it is undefined behavior in CL (SBCL warns).

HIGH: hit-test recurses into children (mouse.lisp:18-34)
  Was returning the root component for any click within its bounds,
  ignoring nested widgets entirely.  Now checks component-children
  first, returning the deepest match.

MEDIUM: Select/TabBar position hardcoded to (0,0)
  Both rendered at terminal origin regardless of layout position.
  Now read layout-node-x/y for absolute positioning.

MEDIUM: Text-input truncation missing
  Render drew full value string even when exceeding widget width.
  Now truncates to (min (length display) w).

MEDIUM: X10 mouse release detection added (input.lisp:219-226)
  X10 encoding uses button=3 for release.  Was detecting all events
  as press/drag.  Now checks button=3 → :release.

MEDIUM: parse-csi-params handles private markers (input.lisp:128-131)
  < = > ? characters (0x3c-0x3f) treated as parameter start markers
  instead of accumulating bogus digit values.  Latent trap removed.

Deferred (pre-existing design):
- Scrollbox visibility cy vs orig-y: match for column layout (common case)
- Nested scrollbox coordinates: assumes sequential layout positions
- text-input cursor drawing: feature, not bugfix

392 tests pass.

src/components/select.lisp

@@ -76,7 +76,9 @@
     (subseq filtered start end)))
 
 (defmethod render ((sel select) backend)
-  (let* ((ln (select-layout-node sel)) (x 0) (y 0)
+  (let* ((ln (select-layout-node sel))
+         (x (if ln (layout-node-x ln) 0))
+         (y (if ln (layout-node-y ln) 0))
          (w (if ln (layout-node-width ln) 80))
          (visible (select-visible-options sel)) (sel-idx (select-selected-index sel)))
     (dolist (item visible)