Move sx docs markup from Python to .sx files (Phase 2)

Migrate ~2,500 lines of SX markup from Python string concatenation in
essays.py to proper .sx defcomp definitions:

- docs-content.sx: 8 defcomps for docs pages (intro, getting-started,
  components, evaluator, primitives, css, server-rendering, home)
- protocols.sx: 6 defcomps for protocol documentation pages
- essays.sx: 9 essay defcomps (pure content, no params)
- examples.sx: template defcomp receiving data values, calls highlight
  internally — Python passes raw code strings, never SX
- reference.sx: 6 defcomps for data-driven reference pages

essays.py reduced from 2,699 to 619 lines. Docs/protocol/essay
functions become one-liners returning component names. Example functions
use sx_call to pass data values to the template. Reference functions
pass data-built component trees via SxExpr.

renders.py: removed _code, _example_code, _placeholder,
_clear_components_btn (now handled by .sx templates).
helpers.py: removed inline hero code building, uses ~sx-home-content.

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

sx/sxc/pages/helpers.py

@@ -7,24 +7,14 @@ from .essays import (
     _reference_index_sx, _reference_attr_detail_sx,
 )
 from .utils import _docs_nav_sx, _reference_nav_sx, _protocols_nav_sx, _examples_nav_sx, _essays_nav_sx
-from content.highlight import highlight
 
 
 def home_content_sx() -> str:
     """Home page content as sx wire format."""
-    hero_code = highlight('(div :class "p-4 bg-white rounded shadow"\n'
-                          '  (h1 :class "text-2xl font-bold" "Hello")\n'
-                          '  (button :sx-get "/api/data"\n'
-                          '    :sx-target "#result"\n'
-                          '    "Load data"))', "lisp")
     return (
-        f'(section :id "main-panel"'
-        f'  :class "flex-1 md:h-full md:min-h-0 overflow-y-auto overscroll-contain js-grid-viewport"'
-        f'  (div :id "main-content"'
-        f'    (~sx-hero {hero_code})'
-        f'    (~sx-philosophy)'
-        f'    (~sx-how-it-works)'
-        f'    (~sx-credits)))'
+        '(section :id "main-panel"'
+        '  :class "flex-1 md:h-full md:min-h-0 overflow-y-auto overscroll-contain js-grid-viewport"'
+        '  (~sx-home-content))'
     )
 
 
@@ -92,25 +82,9 @@ def _register_sx_helpers() -> None:
                 return label
         return None
 
-    def _home_content():
-        """Build home page content (uses highlight for hero code block)."""
-        hero_code = _highlight(
-            '(div :class "p-4 bg-white rounded shadow"\n'
-            '  (h1 :class "text-2xl font-bold" "Hello")\n'
-            '  (button :sx-get "/api/data"\n'
-            '    :sx-target "#result"\n'
-            '    "Load data"))', "lisp")
-        return (
-            f'(div :id "main-content"'
-            f' (~sx-hero {hero_code})'
-            f' (~sx-philosophy)'
-            f' (~sx-how-it-works)'
-            f' (~sx-credits))'
-        )
-
     register_page_helpers("sx", {
         # Content builders
-        "home-content": _home_content,
+        "home-content": lambda: "(~sx-home-content)",
         "docs-content": _docs_content_sx,
         "reference-content": _reference_content_sx,
         "reference-index-content": _reference_index_sx,

sx/sxc/pages/renders.py

@@ -1,26 +1,6 @@
 """Public render/utility functions called from bp routes."""
 from __future__ import annotations
 
-from content.highlight import highlight
-
-
-def _code(code: str, language: str = "lisp") -> str:
-    """Build a ~doc-code component with highlighted content."""
-    highlighted = highlight(code, language)
-    return f'(~doc-code :code {highlighted})'
-
-
-def _example_code(code: str, language: str = "lisp") -> str:
-    """Build an ~example-source component with highlighted content."""
-    highlighted = highlight(code, language)
-    return f'(~example-source :code {highlighted})'
-
-
-def _placeholder(div_id: str) -> str:
-    """Empty placeholder that will be filled by OOB swap on interaction."""
-    from shared.sx.helpers import sx_call
-    return sx_call("doc-placeholder", id=div_id)
-
 
 def _component_source_text(*names: str) -> str:
     """Get defcomp source text for named components."""
@@ -47,12 +27,6 @@ def _oob_code(target_id: str, text: str) -> str:
     return sx_call("doc-oob-code", target_id=target_id, text=text)
 
 
-def _clear_components_btn() -> str:
-    """Button that clears the client-side component cache (localStorage + in-memory)."""
-    from shared.sx.helpers import sx_call
-    return sx_call("doc-clear-cache-btn")
-
-
 def _full_wire_text(sx_src: str, *comp_names: str) -> str:
     """Build the full wire response text showing component defs + CSS note + sx source.