feat(rpc): impl getTokenAccountBalance RPC

src/cmd.zig

@@ -1666,6 +1666,17 @@ fn validator(
         .slot_tracker = &replay_service_state.replay_state.slot_tracker,
     });
 
+    const account_store = sig.accounts_db.AccountStore{
+        .accounts_db_two = &new_db,
+    };
+    try app_base.rpc_hooks.set(
+        allocator,
+        sig.rpc.methods.AccountHookContext{
+            .slot_tracker = &replay_service_state.replay_state.slot_tracker,
+            .account_reader = account_store.reader(),
+        },
+    );
+
     const replay_thread = try replay_service_state.spawnService(
         &app_base,
         if (maybe_vote_sockets) |*vs| vs else null,

src/core/epoch_schedule.zig

@@ -44,6 +44,21 @@ pub const EpochSchedule = extern struct {
         .warmup = true,
     });
 
+    pub fn jsonStringify(self: EpochSchedule, jw: anytype) @TypeOf(jw.*).Error!void {
+        try jw.beginObject();
+        try jw.objectField("slotsPerEpoch");
+        try jw.write(self.slots_per_epoch);
+        try jw.objectField("leaderScheduleSlotOffset");
+        try jw.write(self.leader_schedule_slot_offset);
+        try jw.objectField("warmup");
+        try jw.write(self.warmup);
+        try jw.objectField("firstNormalEpoch");
+        try jw.write(self.first_normal_epoch);
+        try jw.objectField("firstNormalSlot");
+        try jw.write(self.first_normal_slot);
+        try jw.endObject();
+    }
+
     pub fn getEpoch(self: *const EpochSchedule, slot: Slot) Epoch {
         return self.getEpochAndSlotIndex(slot)[0];
     }

src/core/hash.zig

@@ -122,6 +122,10 @@ pub const Hash = extern struct {
         };
     }
 
+    pub fn jsonStringify(self: Hash, jw: anytype) !void {
+        try jw.write(self.base58String().constSlice());
+    }
+
     /// Intended to be used in tests.
     pub fn initRandom(random: std.Random) Hash {
         var data: [SIZE]u8 = undefined;