feat(admin): grant hints to a user's wallet from the console

Add an "Add hints" form on the admin user card that additively tops up a
player's hint wallet (1-100 per grant). The grant is raise-only by
construction (an additive UPDATE never lowers the balance) and stays correct
under a concurrent in-game spend; a per-grant cap bounds a fat-finger, since
the console can never reduce a wallet.

The in-game hint policy is unchanged and already correct: a game offers the
per-seat allowance plus the wallet, spending the allowance first and the
wallet only after (covered by TestHintPolicy).

backend/internal/server/handlers_admin_console.go

@@ -28,6 +28,10 @@ import (
 // adminPageSize is the page size of the admin console's paginated lists.
 const adminPageSize = 50
 
+// maxHintGrant caps a single operator hint grant. Grants are additive and can never lower a
+// wallet, so a fat-fingered grant cannot be undone through this form; the cap bounds one mistake.
+const maxHintGrant = 100
+
 // registerConsole mounts the server-rendered admin console under /_gm. The gateway
 // puts HTTP Basic-Auth in front of /_gm and reverse-proxies it verbatim; the
 // backend trusts the gateway (as for all of /api) and adds only a same-origin guard
@@ -51,6 +55,7 @@ func (s *Server) registerConsole(router *gin.Engine) {
 	gm.GET("/users/:id", s.consoleUserDetail)
 	gm.POST("/users/:id/message", s.consoleUserMessage)
 	gm.POST("/users/:id/clear-high-rate-flag", s.consoleClearHighRateFlag)
+	gm.POST("/users/:id/grant-hints", s.consoleGrantHints)
 	gm.POST("/users/:id/block", s.consoleBlockUser)
 	gm.POST("/users/:id/unblock", s.consoleUnblockUser)
 	gm.GET("/reasons", s.consoleReasons)
@@ -263,8 +268,8 @@ func (s *Server) consoleUserDetail(c *gin.Context) {
 	view := adminconsole.UserDetailView{
 		ID: acc.ID.String(), DisplayName: acc.DisplayName, Language: acc.PreferredLanguage,
 		TimeZone: acc.TimeZone, Guest: acc.IsGuest, NotificationsInAppOnly: acc.NotificationsInAppOnly,
-		PaidAccount: acc.PaidAccount, HintBalance: acc.HintBalance, CreatedAt: fmtTime(acc.CreatedAt),
-		HasStats: !acc.IsGuest, ConnectorEnabled: s.connector != nil,
+		PaidAccount: acc.PaidAccount, HintBalance: acc.HintBalance, HintGrantMax: maxHintGrant,
+		CreatedAt: fmtTime(acc.CreatedAt), HasStats: !acc.IsGuest, ConnectorEnabled: s.connector != nil,
 	}
 	if acc.MergedInto != uuid.Nil {
 		view.MergedInto = acc.MergedInto.String()
@@ -774,6 +779,28 @@ func (s *Server) consoleClearHighRateFlag(c *gin.Context) {
 	s.renderConsoleMessage(c, "Cleared", "high-rate flag cleared", "/_gm/users/"+id.String())
 }
 
+// consoleGrantHints adds hints to a user's wallet. The grant is additive (raise-only): it tops a
+// player up and can never lower what they already hold, so blocking a reduction is inherent rather
+// than a separate guard. A single grant is bounded by maxHintGrant.
+func (s *Server) consoleGrantHints(c *gin.Context) {
+	id, ok := s.consoleUUID(c, "/_gm/users")
+	if !ok {
+		return
+	}
+	back := "/_gm/users/" + id.String()
+	n, err := strconv.Atoi(trimForm(c, "amount"))
+	if err != nil || n < 1 || n > maxHintGrant {
+		s.renderConsoleMessage(c, "Invalid amount", fmt.Sprintf("enter a whole number of hints to add, between 1 and %d", maxHintGrant), back)
+		return
+	}
+	balance, err := s.accounts.GrantHints(c.Request.Context(), id, n)
+	if err != nil {
+		s.consoleError(c, err)
+		return
+	}
+	s.renderConsoleMessage(c, "Granted", fmt.Sprintf("added %d hint(s); the wallet is now %d", n, balance), back)
+}
+
 // consoleBlockUser manually blocks an account: it records the suspension (permanent or until a
 // parsed deadline, snapshotting the chosen reason's en/ru text) and forfeits the player's active
 // games, removing them from matchmaking. The block takes effect on the player's next request.