feat(lang): L11 views and templates - the UI is markup, not code

A `view Name { field = x; function q(..); on e(..) }` declaration is the one bridge between a
program and its UI: it writes view_<name>() -> UiView, whose model is a Value of every field and
whose call runs a query or an event by name.

ludic.ui is a template runtime:
- HTML-shaped XML screens and components, loaded at run time;
- {expression} bindings, if/else/each, props, slots, per-instance state;
- on-press / onclick actions (event, set, emit);
- component libraries (export="true", <import src as>).

Styling:
- stylesheets in <style> or importable .lss files (@import);
- CSS selectors (#id, .class, [attr=v], descendant and > combinators, :hover, :disabled,
  :first-child, :last-child, :nth-child, :not) weighed by specificity;
- the box model and flex under CSS's property names.

Also:
- default parameters, and positional-then-named calls;
- Value gains a float kind;
- a function shadowing a runtime one is refused;
- an index is evaluated before the slice is read;
- runtime errors name the right file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.ui/lib_util.ludic

@@ -0,0 +1,34 @@
+# lib_util.ludic - a file made, found, read, and a path beside another
+function lib_find(names: []string, name: string) -> int {
+  for i in 0 .. len(names) {
+    if names[i] == name { return i }
+  }
+  return -1
+}
+function lib_new(path: string) -> UiFile {
+  let f = new UiFile
+  f.path = path
+  f.names = new []string
+  f.comps = new []UiTpl
+  f.exported = new []bool
+  f.imp_as = new []string
+  f.imp = new []UiFile
+  f.own = new []UiRule
+  push(lib_files, f)
+  return f
+}
+function lib_text(path: string) -> string {
+  var src = ""
+  if ui_be != null and ui_be.read != null { src = ui_be.read(path) } else { src = Fs.read_text(path) }
+  if src == null { return "" }
+  return src
+}
+# `src` read from beside the file that imports it
+function lib_beside(path: string, src: string) -> string {
+  var cut = -1
+  for i in 0 .. len(path) {
+    if path[i] == 47 { cut = i }
+  }
+  if cut < 0 or (len(src) > 0 and src[0] == 47) { return src }
+  return path[0..cut + 1] + src
+}