refactor(audit): batch 2 — remove dead scaffolding from the shipping binary

Two dead-code removals surfaced by the audit; no runtime behavior change.

1. Delete the lite-lifecycle "readiness" scaffold (~1,586 lines). The pure
   dry-run evaluateLiteWalletServerLifecycleReadiness (whose own status text
   says "wallet lifecycle execution is still disabled in this scaffold") had
   zero callers; executeLiteWalletServerSelectionUi had zero callers; and
   executeLiteWalletLifecycleUiRequest's only caller was a fallback in
   settings_page reached only when app->liteWallet() is null. Deleted
   lite_wallet_server_lifecycle_readiness.{h,cpp} and the readiness /
   UI-execution machinery + enums + translation tables from both adapters,
   keeping the genuinely-live helpers (liteConnectionSettingsFromAppSettings,
   applyLiteConnectionSettingsToAppSettings, redactLiteServerSelectionValue,
   and the LiteWalletLifecycleUiExecutionInput DTO the live create/open/
   restore path still uses). The null-backend fallback now sets a plain
   "Lite wallet backend unavailable" status. This is exactly the
   readiness/scaffold pattern CLAUDE.md forbids regrowing.

2. Split the HushChat fixture/capture-manifest/seed-projection tooling
   (~2,050 lines, incl. the libsodium seed-projection) out of
   chat_protocol.cpp (1854 -> 284) and chat_protocol.h (586 -> 105) into a
   new chat_fixture_tooling.{h,cpp} compiled ONLY into the HushChatFixtureCheck
   dev tool — never into the app, lite, or test binaries (verified via nm).
   The app keeps only the runtime slice (memo parsing + tx metadata
   extraction) that network_refresh_service actually calls. Also moved the
   decrypt-preflight/hex helpers, which likewise had no runtime caller.

Note: the HushChat split is on gated-off experimental code and should be
coordinated with the pending dormant-HushChat-content handling (commit
af06b8b) before the lite PR — done here as a pure mechanical split, no redesign.

Full-node + Lite + HushChatFixtureCheck build clean; ctest 1/1; hygiene clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/hushchat_fixture_check.cpp

@@ -1,4 +1,4 @@
-#include "chat/chat_protocol.h"
+#include "chat/chat_fixture_tooling.h"
 
 #include <algorithm>
 #include <filesystem>