browserrot: Node stealth sidecar + AI self-heal (M-B1..M-B3, LIVE-VM)

Extends the Phase A-tier-1 site-side rotation engine with an optional Node
browser-sidecar and a deterministic self-heal tier, all proven LIVE-VM against
the local lab change-password form. go-rod stays the default; the sidecar is a
swap-in Driver behind the same Session/Driver/Rotator interfaces — no spine
change, backup + verify-new-before-revoke-old + proof gates all apply unchanged.

M-B1 sidecar parity: internal/browserrot/sidecar/ (index.js JSON-RPC over stdio,
  patchright real-fingerprint Chromium, playwright-core fallback) + sidecar.go
  Driver/Session. A shared test harness runs go-rod and the sidecar through the
  identical live rotation proof.
M-B2 stealth: patchright removes navigator.webdriver; humanized input (Bezier
  mouse paths + per-key typing jitter, no ML trajectory generation per plan §5).
M-B3 self-heal: Healer interface + heal-retry fill/click/text wrappers; on a
  rotted selector, heal.js relocates the field from DOM structure ONLY (never a
  value) and the engine rewrites + persists the recipe (recipes.go RecipeBook)
  so the next run is Tier-1 again. Deterministic heuristic is the proven Tier-2;
  Stagehand LLM strategy is opt-in + UNPROVEN. Leak-check asserts no secret ever
  reaches a heal request (redacted IPC transcript).

Secret seam documented honestly: fill carries base64 secret bytes across exactly
one local stdio boundary, typed and wiped, never logged/persisted/sent to a
model. MFA/CAPTCHA still degrade to the human worklist (Hard Rule 5).

14 tests green, -race clean; lab/lab-provision-browserrot.sh proves both drivers.
M-B4 (first REAL self-owned site) deliberately NOT started — needs per-credential
authorization (safe-candidate ladder).

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

lab/lab-provision-browserrot.sh

@@ -48,8 +48,45 @@ echo "== using Chromium: $CHROME_BIN"
 # Run from the repo root (the dir containing go.mod).
 cd "$(git -C "$(dirname "$0")" rev-parse --show-toplevel 2>/dev/null || echo "$(dirname "$0")/..")"
 
-echo "== running the LIVE-VM browser-rotation proof =="
+# The Node sidecar (patchright real-fingerprint Chromium) is an OPTIONAL swap-in Driver
+# that must reach parity with go-rod. If a `node` runtime + the sidecar deps are present,
+# prove BOTH drivers through the identical harness; otherwise prove go-rod only.
+SIDECAR_DIR="internal/browserrot/sidecar"
+have_sidecar() {
+  command -v node >/dev/null 2>&1 && [ -d "$SIDECAR_DIR/node_modules/playwright-core" ]
+}
+
+echo "== running the LIVE-VM browser-rotation proof (go-rod) =="
 CHROME_BIN="$CHROME_BIN" go test -run TestIntegration_realBrowserRotation -v ./internal/browserrot/
 
+if have_sidecar; then
+  echo
+  echo "== running the LIVE-VM browser-rotation proof (node-sidecar, parity) =="
+  node --version | sed 's/^/   node /'
+  CHROME_BIN="$CHROME_BIN" go test -run TestIntegration_sidecarBrowserRotation -v ./internal/browserrot/
+
+  if [ -d "$SIDECAR_DIR/node_modules/patchright" ]; then
+    echo
+    echo "== M-B2 stealth: patchright fingerprint + humanized input =="
+    CHROME_BIN="$CHROME_BIN" go test -run 'TestIntegration_sidecarStealth' -v ./internal/browserrot/
+  else
+    echo
+    echo "== M-B2 stealth SKIPPED (patchright not installed) =="
+    echo "   to enable: (cd $SIDECAR_DIR && npm install patchright)"
+  fi
+
+  echo
+  echo "== M-B3 self-heal: rotted selector -> Tier-2 heal -> rewrite recipe (no secret to heal) =="
+  CHROME_BIN="$CHROME_BIN" go test -run 'TestIntegration_sidecarSelfHeal' -v ./internal/browserrot/
+else
+  echo
+  echo "== node-sidecar SKIPPED (no node runtime or deps not installed) =="
+  echo "   to enable: (cd $SIDECAR_DIR && PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm install)"
+fi
+
+echo
+echo "== secret-seam leak guard (browser-free) =="
+go test -run TestSidecar_secretSeamBase64 -v ./internal/browserrot/
+
 echo
 echo "LIVE-VM BROWSER-ROTATION ENGINE PROOF PASSED"