Aser server-affinity component expansion + readline buffer fix

adapter-sx.sx: aser-expand-component expands :affinity :server components
inline during SX wire format serialization. Binds keyword args via
eval-expr, children via aser (handles HTML tags), then asers the body.

ocaml_bridge.py: 10MB readline buffer for large spec responses.
nav-data.sx: evaluator.sx filename fix.

Page rendering stays on Python _eval_slot for now — full OCaml rendering
needs the page shell IO (headers, CSRF, CSS) migrated to OCaml IO bridge.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/adapter-sx.sx

@@ -71,9 +71,13 @@
             (= name "<>")
               (aser-fragment args env)
 
-            ;; Component call — serialize WITHOUT expanding
+            ;; Component call — expand server-affinity, serialize others
             (starts-with? name "~")
-              (aser-call name args env)
+              (let ((comp (if (env-has? env name) (env-get env name) nil)))
+                (if (and comp (component? comp)
+                         (= (component-affinity comp) "server"))
+                  (aser-expand-component comp args env)
+                  (aser-call name args env)))
 
             ;; Lake — serialize (server-morphable slot)
             (= name "lake")
@@ -213,6 +217,53 @@
         (str "(" (join " " parts) ")")))))
 
 
+;; --------------------------------------------------------------------------
+;; Server-affinity component expansion
+;; --------------------------------------------------------------------------
+;;
+;; When a component has :affinity :server, the aser expands it inline:
+;; bind keyword args + children, then aser the body.
+;; This is the aser equivalent of render-to-html's component expansion.
+
+(define aser-expand-component :effects [render]
+  (fn ((comp :as any) (args :as list) (env :as dict))
+    (let ((params (component-params comp))
+          (local (env-merge env (component-closure comp)))
+          (i 0)
+          (skip false)
+          (children (list)))
+      ;; Parse keyword args and positional children from args
+      ;; Keyword values are eval'd (they're data). Children are NOT eval'd
+      ;; (they may contain HTML tags that only the aser can handle).
+      (for-each
+        (fn (arg)
+          (if skip
+            (do (set! skip false) (set! i (inc i)))
+            (if (and (= (type-of arg) "keyword")
+                     (< (inc i) (len args)))
+              ;; Keyword arg: bind name = eval'd next arg
+              (do
+                (env-bind! local (keyword-name arg)
+                  (trampoline (eval-expr (nth args (inc i)) env)))
+                (set! skip true)
+                (set! i (inc i)))
+              ;; Positional child: keep as unevaluated AST for aser
+              (do
+                (append! children arg)
+                (set! i (inc i))))))
+        args)
+      ;; Bind &rest children — aser each child first, then bind the result
+      (when (component-has-children comp)
+        (let ((asered-children
+                (map (fn (c) (aser c env)) children)))
+          (env-bind! local "children"
+            (if (= (len asered-children) 1)
+              (first asered-children)
+              asered-children))))
+      ;; Aser the body in the merged env
+      (aser (component-body comp) local))))
+
+
 ;; --------------------------------------------------------------------------
 ;; Form classification
 ;; --------------------------------------------------------------------------