fix(api): Manabar.CurrentMana use json.RawMessage for string/number ambiguity

current_mana is a share_type that the chain serializes inconsistently:
sometimes as a JSON string ("5640467421072"), sometimes as a number (0).
Using string caused unmarshal failures for accounts with numeric manabar
values. Switch to json.RawMessage (same pattern as reputation/withdrawn).

Author: ety001

protocol/api/accounts.go

@@ -105,8 +105,8 @@ type Authority struct {
 // current_mana is a share_type (int64) and serializes as a JSON string because
 // it can be large; last_update_time is a unix-epoch uint32 emitted as a number.
 type Manabar struct {
-	CurrentMana    string `json:"current_mana"`
-	LastUpdateTime uint32 `json:"last_update_time"`
+	CurrentMana    json.RawMessage `json:"current_mana"`
+	LastUpdateTime uint32           `json:"last_update_time"`
 }
 
 // ExtendedAccount models a full condenser_api.get_accounts response entry,

protocol/api/accounts_test.go

@@ -238,9 +238,9 @@ func TestUnmarshal_ExtendedAccount_FullFixture(t *testing.T) {
 		t.Errorf("savings_withdraw_requests: got %d", acct.SavingsWithdrawRequests)
 	}
 
-	// --- typed Manabar: current_mana is a string, last_update_time a number ---
-	if acct.VotingManabar.CurrentMana != "5640467421072" {
-		t.Errorf("voting_manabar.current_mana: got %q", acct.VotingManabar.CurrentMana)
+	// --- Manabar: current_mana is json.RawMessage (string or number on chain) ---
+	if string(acct.VotingManabar.CurrentMana) != `"5640467421072"` {
+		t.Errorf("voting_manabar.current_mana: got %s", acct.VotingManabar.CurrentMana)
 	}
 	if acct.VotingManabar.LastUpdateTime != 1699768485 {
 		t.Errorf("voting_manabar.last_update_time: got %d", acct.VotingManabar.LastUpdateTime)