telegram: wire daily token budget into production flow

The DailyTokenBudget feature was fully implemented (SetDailyTokenBudget,
CheckDailyBudget, config parsing, tests) but never called from production
code. This commit wires it in:

1. telegramCmd: Call bot.SetDailyTokenBudget during startup when
   cfg.DailyTokenBudget > 0 (0 = unlimited, the default)

2. handleChatMessage — pre-flight check: Before creating the agent,
   call CheckDailyBudget(1) to detect if the budget is already
   exhausted, avoiding a wasted API call. Sends a clear error message.

3. handleChatMessage — post-run billing: After agent.RunWithMessages,
   bill actual input+output tokens via CheckDailyBudget. If exceeded,
   logs a warning and sends a notification to the chat but still
   delivers the response (the API call already happened).

Docs: update TELEGRAM.md to describe pre-flight + post-run billing.

Author: jkyberneees

cmd/odek/telegram.go

@@ -68,6 +68,12 @@ func telegramCmd(args []string) error {
 		bot.SetFallbackURLs(cfg.FallbackURLs)
 	}
 
+	// 4d. Configure daily token budget (0 = unlimited, the default).
+	if cfg.DailyTokenBudget > 0 {
+		bot.SetDailyTokenBudget(cfg.DailyTokenBudget)
+		botLog.Info("daily token budget set", "budget", cfg.DailyTokenBudget)
+	}
+
 	// 5. Create session store on disk (~/.odek/sessions/).
 	store, err := session.NewStore()
 	if err != nil {
@@ -434,6 +440,21 @@ func handleChatMessage(
 
 	rend := render.New(os.Stderr, false).WithModel(modelLabel)
 
+	// ── Pre-flight budget check ────────────────────────────────────
+	// Before running the agent, check if the daily budget is already
+	// exhausted — avoids burning an API call just to be rejected.
+	if resolved.Telegram.DailyTokenBudget > 0 {
+		if err := bot.CheckDailyBudget(1); err != nil {
+			reportError(bot, chatID, fmt.Sprintf(
+				"Daily token budget exhausted: %v. "+
+					"The budget resets at midnight UTC. "+
+					"Set daily_token_budget to 0 in config for unlimited usage.",
+				err,
+			))
+			return
+		}
+	}
+
 	// ── Typing Indicator ────────────────────────────────────────────
 	// Send "typing" action every 4s while the agent runs (Telegram shows
 	// it for ~5s). Fire-and-forget so a hanging HTTP call doesn't block
@@ -584,6 +605,22 @@ func handleChatMessage(
 		return
 	}
 
+	// Bill actual token usage against daily budget (if configured).
+	tokensUsed := int64(runInfo.InputTokens + runInfo.OutputTokens)
+	if tokensUsed > 0 {
+		if err := bot.CheckDailyBudget(tokensUsed); err != nil {
+			// Budget exceeded — report it but still deliver the response.
+			log.Warn("daily token budget exceeded",
+				"chat_id", chatID, "tokens", tokensUsed, "error", err)
+			bot.SendMessage(chatID, fmt.Sprintf(
+				"⚠️ *Token budget warning*\\n\\n%v\\n\\n"+
+					"Further agent runs may be blocked until the daily budget resets. "+
+					"Use `/stats` to check current usage.",
+				err,
+			), &telegram.SendOpts{ParseMode: telegram.ParseModeMarkdownV2})
+		}
+	}
+
 	// Save the updated session messages.
 	cs.Messages = updatedMessages
 	cs.TurnCount++

docs/TELEGRAM.md

@@ -87,8 +87,11 @@ The `Bot` struct is a lightweight Telegram Bot API client built on the standard
 `SetDailyTokenBudget` and `CheckDailyBudget` implement a simple daily token usage tracker:
 - Usage is persisted to `~/.odek/telegram_token_usage_<YYYY-MM-DD>`
 - Budget resets automatically each calendar day
-- Returns an error if the total exceeds the configured budget
-- No-op when budget is 0 (unlimited)
+- **Pre-flight check**: before each agent run, a lightweight check verifies the budget isn't already exhausted, avoiding wasted API calls
+- **Post-run billing**: after each agent run, actual token usage (`input + output`) is deducted from the daily budget
+- Returns a warning message to the chat if the budget is exceeded, but still delivers the response
+- No-op when budget is 0 (unlimited, the default)
+- Configurable via `ODEK_TELEGRAM_DAILY_TOKEN_BUDGET` env var or `daily_token_budget` in `odek.json`
 
 ## Long-Polling (`poller.go`)