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).

env/optimize.env

@@ -0,0 +1,20 @@
+
+# Build mode. The DEFAULT is an optimized -O3 build (what installs and releases
+# use). Opt into other modes explicitly:
+#     DEBUG=1     -> debug build: -O0 -g + AddressSanitizer (development)
+#     NOPYTHON=1  -> -O0 -g -DNOPYTHON, no ASan (build without the interpreter)
+# `override` is used throughout so that a stray command-line or environment
+# `OPTIMIZE=...` cannot leak into CXXFLAGS: OPTIMIZE is an internal flag string
+# here, no longer a trigger. (A legacy `make OPTIMIZE=1` still yields -O3, since
+# it falls through to the optimized default below.)
+ifdef DEBUG
+override OPTIMIZE := -O0 -g
+SANITIZE := -fsanitize=address -fno-omit-frame-pointer
+else ifdef NOPYTHON
+override OPTIMIZE := -O0 -g -DNOPYTHON
+SANITIZE :=
+else
+# Performance build (default).
+override OPTIMIZE := -O3
+SANITIZE :=
+endif