host/engine: visible error/retry state for failed fetches + retry on network failure

Two engine fixes in web/orchestration.sx (rebuilt into the WASM bytecode) plus the
blog CSS that surfaces them.

1. Retry on NETWORK failure, not just HTTP errors. The fetch error/catch path (the
   real offline / DNS / connection-refused case) previously dispatched
   sx:requestError and stopped — only a non-ok HTTP response with an empty body
   ever reached handle-retry. So "no connection" never recovered. Now the catch
   path calls handle-retry too, so an sx-retry element actually self-heals when the
   connection returns (the cap bounds the backoff interval, not the attempt count —
   it retries forever).

2. Visible failure state. On any failed/aborted fetch the engine adds an `.sx-error`
   class to the element (cleared, with the retry backoff reset, on the next
   success). Without it a stuck retry loop is invisible — the picker just sits
   "Loading…". The blog shell ships CSS so the relate picker shows "Connection
   problem — retrying…" / "offline, retrying…" on .sx-error.

Platform-wide: any sx-get/sx-post element benefits, not just the picker.

Tests: relate-picker.spec.js gains a 6th case — abort relate-options, assert
.sx-error appears, un-abort, assert it clears and the picker repopulates (proving
the retry loop is live). 6/6 browser + 272/272 conformance. WASM web stack rebuilt
(orchestration.sxbc + the static hs-* copies refreshed by the same build).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

shared/static/wasm/sx/module-manifest.json

@@ -951,7 +951,26 @@
       "hs-keywords",
       "hs-keyword?",
       "hs-tokenize",
-      "hs-tokenize-template"
+      "hs-tokenize-template",
+      "hs-stream-type-map",
+      "hs-stream",
+      "hs-stream-skip-ws!",
+      "hs-stream-current",
+      "hs-stream-match",
+      "hs-stream-match-type",
+      "hs-stream-match-any",
+      "hs-stream-match-any-op",
+      "hs-stream-peek",
+      "hs-stream-consume-until",
+      "hs-stream-consume-until-ws",
+      "hs-stream-push-follow!",
+      "hs-stream-pop-follow!",
+      "hs-stream-push-follows!",
+      "hs-stream-pop-follows!",
+      "hs-stream-clear-follows!",
+      "hs-stream-restore-follows!",
+      "hs-stream-last-match",
+      "hs-stream-last-ws"
     ]
   },
   "hs-parser": {
@@ -989,6 +1008,8 @@
       "hs-each",
       "meta",
       "hs-on-every",
+      "hs-throttle!",
+      "hs-debounce!",
       "_hs-on-caller",
       "hs-on",
       "hs-on-every",
@@ -1067,6 +1088,7 @@
       "hs-eq-ignore-case",
       "hs-starts-with?",
       "hs-ends-with?",
+      "hs-attr-watch!",
       "hs-scoped-set!",
       "hs-scoped-get",
       "hs-precedes?",
@@ -1156,8 +1178,6 @@
       "hs-token-value",
       "hs-token-op?",
       "hs-try-json-parse",
-      "hs-socket-normalise-url",
-      "hs-socket-bind-name!",
       "hs-socket-resolve-rpc!",
       "hs-socket-register!"
     ]