Refactor SX primitives: modular, isomorphic, general-purpose

Spec modularization:
- Add (define-module :name) markers to primitives.sx creating 11 modules
  (7 core, 4 stdlib). Bootstrappers can now selectively include modules.
- Add parse_primitives_by_module() to boundary_parser.py.
- Remove split-ids primitive; inline at 4 call sites in blog/market queries.

Python file split:
- primitives.py: slimmed to registry + core primitives only (~350 lines)
- primitives_stdlib.py: NEW — stdlib primitives (format, text, style, debug)
- primitives_ctx.py: NEW — extracted 12 page context builders from IO
- primitives_io.py: add register_io_handler decorator, auto-derive
  IO_PRIMITIVES from registry, move sync IO bridges here

JS parity fixes:
- = uses === (strict equality), != uses !==
- round supports optional ndigits parameter
- concat uses nil-check not falsy-check (preserves 0, "", false)
- escape adds single quote entity (') matching Python/markupsafe
- assert added (was missing from JS entirely)

Bootstrapper modularization:
- PRIMITIVES_JS_MODULES / PRIMITIVES_PY_MODULES dicts keyed by module
- --modules CLI flag for selective inclusion (core.* always included)
- Regenerated sx-ref.js and sx_ref.py with all fixes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/ref/sx_ref.py

@@ -656,7 +656,8 @@ _b_int = int
 
 PRIMITIVES = {}
 
-# Arithmetic
+
+# core.arithmetic
 PRIMITIVES["+"] = lambda *args: _b_sum(args)
 PRIMITIVES["-"] = lambda a, b=None: -a if b is None else a - b
 PRIMITIVES["*"] = lambda *args: _sx_mul(*args)
@@ -680,7 +681,8 @@ def _sx_mul(*args):
         r *= a
     return r
 
-# Comparison
+
+# core.comparison
 PRIMITIVES["="] = lambda a, b: a == b
 PRIMITIVES["!="] = lambda a, b: a != b
 PRIMITIVES["<"] = lambda a, b: a < b
@@ -688,28 +690,12 @@ PRIMITIVES[">"] = lambda a, b: a > b
 PRIMITIVES["<="] = lambda a, b: a <= b
 PRIMITIVES[">="] = lambda a, b: a >= b
 
-# Logic
+
+# core.logic
 PRIMITIVES["not"] = lambda x: not sx_truthy(x)
 
-# String
-PRIMITIVES["str"] = sx_str
-PRIMITIVES["upper"] = lambda s: str(s).upper()
-PRIMITIVES["lower"] = lambda s: str(s).lower()
-PRIMITIVES["trim"] = lambda s: str(s).strip()
-PRIMITIVES["split"] = lambda s, sep=" ": str(s).split(sep)
-PRIMITIVES["join"] = lambda sep, coll: sep.join(coll)
-PRIMITIVES["replace"] = lambda s, old, new: s.replace(old, new)
-PRIMITIVES["starts-with?"] = lambda s, p: str(s).startswith(p)
-PRIMITIVES["ends-with?"] = lambda s, p: str(s).endswith(p)
-PRIMITIVES["slice"] = lambda c, a, b=None: c[a:b] if b is not None else c[a:]
-PRIMITIVES["concat"] = lambda *args: _b_sum((a for a in args if a), [])
-PRIMITIVES["strip-tags"] = lambda s: _strip_tags(str(s))
 
-import re as _re
-def _strip_tags(s):
-    return _re.sub(r"<[^>]+>", "", s)
-
-# Predicates
+# core.predicates
 PRIMITIVES["nil?"] = lambda x: x is None or x is NIL
 PRIMITIVES["number?"] = lambda x: isinstance(x, (int, float)) and not isinstance(x, bool)
 PRIMITIVES["string?"] = lambda x: isinstance(x, str)
@@ -727,7 +713,22 @@ PRIMITIVES["odd?"] = lambda n: n % 2 != 0
 PRIMITIVES["even?"] = lambda n: n % 2 == 0
 PRIMITIVES["zero?"] = lambda n: n == 0
 
-# Collections
+
+# core.strings
+PRIMITIVES["str"] = sx_str
+PRIMITIVES["upper"] = lambda s: str(s).upper()
+PRIMITIVES["lower"] = lambda s: str(s).lower()
+PRIMITIVES["trim"] = lambda s: str(s).strip()
+PRIMITIVES["split"] = lambda s, sep=" ": str(s).split(sep)
+PRIMITIVES["join"] = lambda sep, coll: sep.join(coll)
+PRIMITIVES["replace"] = lambda s, old, new: s.replace(old, new)
+PRIMITIVES["starts-with?"] = lambda s, p: str(s).startswith(p)
+PRIMITIVES["ends-with?"] = lambda s, p: str(s).endswith(p)
+PRIMITIVES["slice"] = lambda c, a, b=None: c[a:b] if b is not None else c[a:]
+PRIMITIVES["concat"] = lambda *args: _b_sum((a for a in args if a), [])
+
+
+# core.collections
 PRIMITIVES["list"] = lambda *args: _b_list(args)
 PRIMITIVES["dict"] = lambda *args: {args[i]: args[i+1] for i in _b_range(0, _b_len(args)-1, 2)}
 PRIMITIVES["range"] = lambda a, b, step=1: _b_list(_b_range(_b_int(a), _b_int(b), _b_int(step)))
@@ -739,22 +740,19 @@ PRIMITIVES["rest"] = lambda c: c[1:] if c else []
 PRIMITIVES["nth"] = lambda c, n: c[n] if c and 0 <= n < _b_len(c) else NIL
 PRIMITIVES["cons"] = lambda x, c: [x] + (c or [])
 PRIMITIVES["append"] = lambda c, x: (c or []) + [x]
+PRIMITIVES["chunk-every"] = lambda c, n: [c[i:i+n] for i in _b_range(0, _b_len(c), n)]
+PRIMITIVES["zip-pairs"] = lambda c: [[c[i], c[i+1]] for i in _b_range(_b_len(c)-1)]
+
+
+# core.dict
 PRIMITIVES["keys"] = lambda d: _b_list((d or {}).keys())
 PRIMITIVES["vals"] = lambda d: _b_list((d or {}).values())
 PRIMITIVES["merge"] = lambda *args: _sx_merge_dicts(*args)
 PRIMITIVES["assoc"] = lambda d, *kvs: _sx_assoc(d, *kvs)
 PRIMITIVES["dissoc"] = lambda d, *ks: {k: v for k, v in d.items() if k not in ks}
-PRIMITIVES["chunk-every"] = lambda c, n: [c[i:i+n] for i in _b_range(0, _b_len(c), n)]
-PRIMITIVES["zip-pairs"] = lambda c: [[c[i], c[i+1]] for i in _b_range(_b_len(c)-1)]
 PRIMITIVES["into"] = lambda target, coll: (_b_list(coll) if isinstance(target, _b_list) else {p[0]: p[1] for p in coll if isinstance(p, _b_list) and _b_len(p) >= 2})
 PRIMITIVES["zip"] = lambda *colls: [_b_list(t) for t in _b_zip(*colls)]
 
-# Format
-PRIMITIVES["format-decimal"] = lambda v, p=2: f"{float(v):.{p}f}"
-PRIMITIVES["parse-int"] = lambda v, d=0: _sx_parse_int(v, d)
-PRIMITIVES["pluralize"] = lambda n, s="", p="s": s if n == 1 else p
-PRIMITIVES["escape"] = escape_html
-
 def _sx_merge_dicts(*args):
     out = {}
     for d in args:
@@ -768,12 +766,36 @@ def _sx_assoc(d, *kvs):
         out[kvs[i]] = kvs[i + 1]
     return out
 
+
+# stdlib.format
+PRIMITIVES["format-decimal"] = lambda v, p=2: f"{float(v):.{p}f}"
+PRIMITIVES["parse-int"] = lambda v, d=0: _sx_parse_int(v, d)
+PRIMITIVES["parse-datetime"] = lambda s: str(s) if s else NIL
+
 def _sx_parse_int(v, default=0):
     try:
         return _b_int(v)
     except (ValueError, TypeError):
         return default
 
+
+# stdlib.text
+PRIMITIVES["pluralize"] = lambda n, s="", p="s": s if n == 1 else p
+PRIMITIVES["escape"] = escape_html
+PRIMITIVES["strip-tags"] = lambda s: _strip_tags(str(s))
+
+import re as _re
+def _strip_tags(s):
+    return _re.sub(r"<[^>]+>", "", s)
+
+
+# stdlib.style — stubs (CSSX needs full runtime)
+
+
+# stdlib.debug
+PRIMITIVES["assert"] = lambda cond, msg="Assertion failed": (_ for _ in ()).throw(RuntimeError(f"Assertion error: {msg}")) if not sx_truthy(cond) else True
+
+
 def is_primitive(name):
     if name in PRIMITIVES:
         return True
@@ -1161,4 +1183,4 @@ def render(expr, env=None):
 
 def make_env(**kwargs):
     """Create an environment dict with initial bindings."""
-    return dict(kwargs)
+    return dict(kwargs)