Fix empty code blocks: rename ~docs/code param, fix batched IO dispatch

Two bugs caused code blocks to render empty across the site:

1. ~docs/code component had parameter named `code` which collided with
   the HTML <code> tag name. Renamed to `src` and updated all 57
   callers. Added font-mono class for explicit monospace.

2. Batched IO dispatch in ocaml_bridge.py only skipped one leading
   number (batch ID) but the format has two (epoch + ID):
   (io-request EPOCH ID "name" args...). Changed to skip all leading
   numbers so the string name is correctly found. This fixes highlight
   and other batchable helpers returning empty results.

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

shared/sx/ocaml_bridge.py

@@ -716,10 +716,12 @@ class OcamlBridge:
         if len(parts) < 2:
             raise OcamlBridgeError(f"Malformed io-request: {line}")
 
-        # Skip numeric batch ID if present
+        # Skip leading numeric IDs (epoch, batch ID, or both)
         offset = 1
-        if isinstance(parts[1], (int, float)):
-            offset = 2
+        while offset < len(parts) and isinstance(parts[offset], (int, float)):
+            offset += 1
+        if offset >= len(parts):
+            raise OcamlBridgeError(f"Malformed io-request (no name after IDs): {line}")
         req_name = _to_str(parts[offset])
         args = parts[offset + 1:]