Typed arguments, calculated tables, spans, closed-world fonts, top-level fnt/ and env/

Sync with klammertext-dev through b90b0e09:

- Argument types end to end: :python_cast values are applied (Python
  @eval receives real bools/numbers/lists), argument values are
  validated against their argtype patterns with the argtype's
  description as the error message, argtypes can declare :default
  (overridable per declaration), and parameterized type families are
  supported: rest(N) casts a rest argument to an N-dimensional list
  (bar-count = dimension).
- Unified indexed_range syntax (selector with parenthesized subsets,
  composable mnemonic names) for table lines and spans.
- Table klammer: caption fonts fixed in both targets, :column_width /
  :leading / :colsep wired, :colspan and :rowspan render (HTML
  attributes; \multicolumn / \multirow), calculated cell values (:calc)
  with prefix operators, display-precision semantics, :calc_format and
  :decimal period|comma.
- Fonts: closed-world resolution on the Klammertext font store
  (infrastructure in mac/font_store; no Google Fonts links or fetch).
  Default fonts live in the top-level fnt/; additional fonts install
  into KLAMMERTEXT_FONTS directories via kdesc --font (list, samples,
  preview, install — classification by font metadata).  CSS font family
  names are quoted (digit-initial families were silently lost).
- Environment files moved from mac/env/ to the top-level env/; shell
  profiles source env/runtime.env.  Dead per-host variants removed.
- Container: fnt/ ships in the image; curl removed (no network use).

sks/kutil/kutil.py

@@ -91,20 +91,32 @@ def caption_marker(name, caption, delimiter=" - "):
         caption = f"{delimiter}{caption}"
     return f"{d}{name}{d}{caption}{d}"
 
+def rest_split(s, dimensions=1):
+    """Split bar-delimited text into nested lists, one level per dimension.
+
+    The delimiter for dimension n is a run of exactly n bar characters:
+    | separates elements, || separates lists of elements, ||| lists of
+    lists, and so on.  This is the cast behind the rest(N) argument type.
+    One trailing top-level delimiter (the customary dangling separator
+    before a closing @) is removed; all other empty elements are
+    preserved, so a trailing | still makes an empty final cell.
+    """
+    s = s.strip()
+    if not s:
+        return [] if dimensions > 0 else s
+    delimiter = "|" * dimensions
+    if s.endswith(delimiter) and not s.endswith("|" + delimiter):
+        s = s[:-len(delimiter)]
+    return _rest_split_level(s, dimensions)
+
+def _rest_split_level(s, dimensions):
+    if dimensions <= 0:
+        return s.strip()
+    pattern = re.compile("(?<!\\|)" + "\\|" * dimensions + "(?!\\|)")
+    return [_rest_split_level(part, dimensions - 1) for part in pattern.split(s)]
+
 def rest_args(s, dimensions=1):
-    if s.endswith("||"):
-        s = s[:-2]
-    s = re.sub(r"\t", r"\\t", s)
-    double_bar_pat = re.compile(r"\|\|")
-    bar_pat = re.compile(r"\s*\|\s*")
-    parts = [e.strip() for e in double_bar_pat.split(s.strip())]
-    for p in parts:
-        elts = bar_pat.split(p.strip())
-        elts = ["~" if (e.strip() == "") else e.strip() for e in elts]
-    result = [bar_pat.split(e) for e in parts]
-    if dimensions == 1:
-        result = result[0]
-    return result
+    return rest_split(s, dimensions)
 
 def parse_length(target, s, rel_fraction):
     def choose(html_value, tex_value):