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/target/html_util.h

@@ -76,8 +76,6 @@ namespace html {
     //HTML preamble();
     //HTML head(strings_t css_filenames, strings_t js_filenames);
 
-    void install_local_fonts(strings_t font_dirs, strings_t names, std::string output_dir);
-
     elements_t page(
         std::string title,
         std::string page_title,
@@ -93,7 +91,6 @@ namespace html {
         strings_t css_filenames = {},
         strings_t js_filenames = {},
         strings_t local_fonts = {},
-        strings_t google_fonts = {},
         std::string logo = {});
 
     void add_title(elements_t& body, std::string title, std::string logo="");
@@ -108,8 +105,7 @@ namespace html {
         elements_t body,
         std::string page_title, std::string css,
         std::vector<std::string> css_filenames,
-        std::vector<std::string> local_fonts,
-        std::vector<std::string> google_fonts);
+        std::vector<std::string> local_fonts);
 
     bool tag_is_block_element(std::string tag);
     std::string make_paragraphs(std::string html_text);