fix(admin): shorten the receipt letter, show the account id

The receipt letter repeated what the receipt itself states. It now carries the
amount, the moment of payment with its offset, and the link — the receipt is
the document, and it opens without authentication, so there is nothing for the
two to disagree about. Subject reworded to name what it is.

The ledger and tax-export tables labelled the account link "card", meaning the
user card. On pages about payments that reads as a bank card, which is exactly
how it was misread. Both now show the first eight characters of the account id,
so the column carries data — two rows from the same buyer are visible at a
glance — while the link still holds the whole id.

backend/internal/adminconsole/views.go

@@ -785,18 +785,21 @@ type LedgerView struct {
 // spend, an admin grant, a rewarded-video credit). Refundable marks a funded order the operator may
 // still reverse, which is what puts the Refund button on that row.
 type LedgerRow struct {
-	At         string
-	AccountID  string
-	Kind       string
-	Source     string
-	Origin     string
-	ChipsDelta int
-	Money      string
-	Title      string
-	Order      string
-	Provider   string
-	Shop       string
-	Refundable bool
+	At string
+	// AccountID is the link target; AccountShort is what the cell shows, because a ledger row has
+	// no room for a full uuid and the operator mostly needs to spot two rows from the same buyer.
+	AccountID    string
+	AccountShort string
+	Kind         string
+	Source       string
+	Origin       string
+	ChipsDelta   int
+	Money        string
+	Title        string
+	Order        string
+	Provider     string
+	Shop         string
+	Refundable   bool
 }
 
 // LedgerTotalsRow is the summary above the table, over everything the filter matches. Money is
@@ -841,23 +844,25 @@ type MyNalogBacklogRow struct {
 // sent, which is also what an operator must type when filing by hand — the two have to match, or a
 // later automatic recovery would not recognise the receipt.
 type MyNalogRow struct {
-	LedgerID    string
-	AccountID   string
-	At          string
-	Amount      string
-	Name        string
-	Status      string
-	Attempts    int
-	LastError   string
-	ReceiptUUID string
-	ReceiptURL  string
+	LedgerID     string
+	AccountID    string
+	AccountShort string
+	At           string
+	Amount       string
+	Name         string
+	Status       string
+	Attempts     int
+	LastError    string
+	ReceiptUUID  string
+	ReceiptURL   string
 }
 
 // MyNalogCancelRow is one registered receipt whose income has been refunded and which is therefore
 // owed an annulment.
 type MyNalogCancelRow struct {
-	LedgerID    string
-	AccountID   string
-	ReceiptUUID string
-	Failed      bool
+	LedgerID     string
+	AccountID    string
+	AccountShort string
+	ReceiptUUID  string
+	Failed       bool
 }