Update reference docs: fix event names, add demos, document sx-boost target

- Remove sx:afterSettle (not dispatched), rename sx:sendError → sx:requestError
- Add sx:clientRoute event (Phase 3 client-side routing)
- Add working demos for all 10 events (afterRequest, afterSwap, requestError,
  clientRoute, sseOpen, sseMessage, sseError were missing demos)
- Update sx-boost docs: configurable target selector, client routing behavior
- Remove app-specific nav logic from orchestration.sx, use sx:clientRoute event
- Pass page content deps to sx_response for component loading after server fallback

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

shared/sx/helpers.py

@@ -456,14 +456,18 @@ def sx_call(component_name: str, **kwargs: Any) -> str:
 
 
 
-def components_for_request(source: str = "") -> str:
+def components_for_request(source: str = "",
+                           extra_names: set[str] | None = None) -> str:
     """Return defcomp/defmacro source for definitions the client doesn't have yet.
 
     Reads the ``SX-Components`` header (comma-separated component names
     like ``~card,~nav-item``) and returns only the definitions the client
     is missing.  If *source* is provided, only sends components needed
-    for that source (plus transitive deps).  If the header is absent,
-    returns all needed defs.
+    for that source (plus transitive deps).
+
+    *extra_names* — additional component names to include beyond what
+    *source* references.  Used by defpage to send components the page's
+    content expression needs for client-side routing.
     """
     from quart import request
     from .jinja_bridge import _COMPONENT_ENV
@@ -477,6 +481,12 @@ def components_for_request(source: str = "") -> str:
     else:
         needed = None  # all
 
+    # Merge in extra names (e.g. from page content expression deps)
+    if extra_names and needed is not None:
+        needed = needed | extra_names
+    elif extra_names:
+        needed = extra_names
+
     loaded_raw = request.headers.get("SX-Components", "")
     loaded = set(loaded_raw.split(",")) if loaded_raw else set()
 
@@ -510,7 +520,8 @@ def components_for_request(source: str = "") -> str:
 
 
 def sx_response(source: str, status: int = 200,
-                   headers: dict | None = None):
+                   headers: dict | None = None,
+                   extra_component_names: set[str] | None = None):
     """Return an s-expression wire-format response.
 
     Takes a raw sx string::
@@ -520,6 +531,10 @@ def sx_response(source: str, status: int = 200,
     For SX requests, missing component definitions are prepended as a
     ``<script type="text/sx" data-components>`` block so the client
     can process them before rendering OOB content.
+
+    *extra_component_names* — additional component names to include beyond
+    what *source* references.  Used by defpage to send components the page's
+    content expression needs for client-side routing.
     """
     from quart import request, Response
 
@@ -535,7 +550,7 @@ def sx_response(source: str, status: int = 200,
     # For SX requests, prepend missing component definitions
     comp_defs = ""
     if request.headers.get("SX-Request"):
-        comp_defs = components_for_request(source)
+        comp_defs = components_for_request(source, extra_names=extra_component_names)
         if comp_defs:
             body = (f'<script type="text/sx" data-components>'
                     f'{comp_defs}</script>\n{body}')