web: boosted links read href FRESH at click time — fix stale nav after a morph swap

Reported: on blog.rose-ash.com, home --boosted nav--> a post --click "edit"--> lands on
/tags (a HOME footer link), not /<slug>/edit; subsequent navs stop updating.

Root cause: an innerHTML boost swap uses morph-children, which REUSES DOM nodes in place
(matched positionally when links have no id). The home footer's <a href="/tags"> element is
re-purposed as the post's <a href="/compose-demo/edit"> — its href attribute is rewritten,
but bind-client-route-click had captured the OLD href in its click closure, and the element's
is-processed? mark survived the morph (so boost-descendants skipped re-binding it). Clicking
the reused "edit" link fired the stale /tags closure.

Fix: bind-client-route-click now reads the href FRESH from the element at click time
(dom-get-attr link "href", falling back to the captured value) instead of trusting the
closure. A reused node then always follows its CURRENT href — robust to morph reuse without
needing to clear marks or remove listeners. Recompiled the web stack (.sxbc + manifest).

TEST-FIRST: lib/host/playwright/{boost-nav.spec.js, run-boost-nav-check.sh} reproduces the
exact flow (home -> boosted nav -> click edit -> assert URL is /compose-demo/edit, NOT /tags)
against an ephemeral server. Confirmed RED before the fix (landed on /tags), GREEN after. No
regressions: relate-picker 3/3 (incl. boosted-nav populate) + block-editor 1/1 still pass.

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

lib/host/playwright/run-boost-nav-check.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Regression harness for the boosted-nav link-rebinding bug (composition step polish).
+# Spins up an EPHEMERAL host server (this worktree's binary + lib + web + WASM), which on
+# boot seeds /compose-demo and the home footer's /tags link, runs boost-nav.spec.js in the
+# main worktree's Playwright, then tears down. No live-site dependency.
+#
+#   bash lib/host/playwright/run-boost-nav-check.sh
+#
+# Requires: the OCaml binary built + Playwright + chromium in /root/rose-ash.
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+ROOT=$(pwd)
+
+PORT="${BOOST_PORT:-8914}"
+PW_DIR="${PW_DIR:-/root/rose-ash}"
+USER="admin"; PASS="boost-check-pw"; SECRET="boost-check-secret"
+PDIR=$(mktemp -d)
+SPEC_SRC="lib/host/playwright/boost-nav.spec.js"
+SPEC_DST="$PW_DIR/tests/playwright/_boost-nav-check.spec.js"
+SERVE_LOG=$(mktemp)
+
+cleanup() {
+  [ -n "${SVPID:-}" ] && kill "$SVPID" 2>/dev/null
+  local pid
+  pid=$(ss -lptn "sport = :$PORT" 2>/dev/null | grep -oE 'pid=[0-9]+' | head -1 | cut -d= -f2)
+  [ -n "$pid" ] && kill "$pid" 2>/dev/null
+  rm -f "$SPEC_DST" "$SERVE_LOG"; rm -rf "$PDIR"
+}
+trap cleanup EXIT
+
+echo "== starting ephemeral host server on :$PORT (persist=$PDIR) =="
+SX_SERVING_JIT=1 HOST_PORT="$PORT" SX_PERSIST_DIR="$PDIR" \
+  SX_ADMIN_USER="$USER" SX_ADMIN_PASSWORD="$PASS" SX_SESSION_SECRET="$SECRET" \
+  bash lib/host/serve.sh >"$SERVE_LOG" 2>&1 &
+SVPID=$!
+for i in $(seq 1 60); do
+  curl -sf -o /dev/null "http://127.0.0.1:$PORT/health" 2>/dev/null && break
+  sleep 1
+  [ "$i" = "60" ] && { echo "server never came up:"; cat "$SERVE_LOG"; exit 1; }
+done
+echo "== server up =="
+
+echo "== running Playwright =="
+cp "$ROOT/$SPEC_SRC" "$SPEC_DST"
+cd "$PW_DIR"
+SX_TEST_URL="http://127.0.0.1:$PORT" \
+  node_modules/.bin/playwright test _boost-nav-check.spec.js --workers=1 \
+  --config tests/playwright/playwright.config.js
+RC=$?
+echo "== done (exit $RC) =="
+exit $RC