fix: revert all unrelated upstream develop changes from phase-7 PR

Reverts 259 files that carried unrelated upstream changes through the
phase-6 merge: enum class removals (cppcoreguidelines-use-enum-class),
scoped_lock→lock_guard conversions (modernize-use-scoped-lock),
nodestore Backend API changes (void const* key), .clang-tidy config,
test infrastructure deletions, and miscellaneous develop changes.

These changes belong on develop, not in the telemetry PR chain.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

include/xrpl/protocol/STPathSet.h

@@ -25,6 +25,8 @@ class STPathElement final : public CountedObject<STPathElement>
     std::size_t hash_value_;
 
 public:
+    // Bitwise values (typeCurrency | typeMPT)
+    // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
     enum Type {
         typeNone = 0x00,
         typeAccount = 0x01,   // Rippling through an account (vs taking an offer).