feat(secrets): egress-time credential injection with process-local sentinels (#102009)

* feat(secrets): resolve SecretRef model credentials at egress via process-local sentinels

SecretRef-managed model-provider credentials now travel as opaque
oc-sent-v1 sentinels through auth storage, stream options, and SDK
config; the guarded model fetch injects real values into headers and
URLs immediately before the SSRF-guarded send and fails closed on
unknown sentinels. packages/ai adapters converge on the host guarded
fetch where the SDK supports custom fetch and unwrap at construction
where it does not. Resolved values (and their percent-encoded forms)
register for exact-value log redaction. Kill switch:
OPENCLAW_SECRET_SENTINELS=off. Also fixes a pre-existing unhandled
rejection race in capNonOkResponseBodyLazily (pipeThrough writer leak).

* test(plugin-sdk): update public surface budget

scripts/plugin-sdk-surface-report.mjs

@@ -195,12 +195,12 @@ export function readPluginSdkSurfaceBudgets(env = process.env) {
     ),
     publicExports: readPluginSdkSurfaceBudgetEnv(
       "OPENCLAW_PLUGIN_SDK_MAX_PUBLIC_EXPORTS",
-      10463,
+      10464,
       env,
     ),
     publicFunctionExports: readPluginSdkSurfaceBudgetEnv(
       "OPENCLAW_PLUGIN_SDK_MAX_PUBLIC_FUNCTION_EXPORTS",
-      5220,
+      5221,
       env,
     ),
     publicDeprecatedExports: readPluginSdkSurfaceBudgetEnv(