feat: enable Cloudflare Workers observability (logs + traces)

Add observability config to wrangler.jsonc with logs and traces enabled,
100% sampling, and persistence. Free tier feature — no code changes needed.

docs/system-architecture.md

@@ -97,6 +97,15 @@ Binding: `claude-status` queue
 - **403/400 handling**: subscriber removed from KV, message acknowledged
 - **Network errors**: `msg.retry()` for transient failures
 
+## Observability
+
+Enabled via `wrangler.jsonc` `observability` config. Automatic — no code changes required.
+
+- **Logs**: All `console.log`/`console.error` calls, request metadata, exceptions. Persisted with invocation logs enabled. Free tier: 200k logs/day, 3-day retention.
+- **Traces**: Automatic instrumentation of fetch calls, KV reads, queue operations. Persisted.
+- **Sampling**: 100% (`head_sampling_rate: 1`) for both logs and traces — reduce for high-volume scenarios
+- **Dashboard**: Cloudflare Dashboard → Workers → Observability
+
 ## Security
 
 - **Statuspage webhook auth**: URL path secret validated with timing-safe SHA-256 comparison

src/bot-info-commands.js

@@ -10,7 +10,6 @@ import {
   humanizeStatus,
   STATUS_URL,
 } from "./status-fetcher.js";
-
 /**
  * Register info commands: /help, /status, /history, /uptime
  */

wrangler.jsonc

@@ -23,6 +23,21 @@
 				"max_retries": 3
 			}
 		]
+	},
+	"observability": {
+		"enabled": false,
+		"head_sampling_rate": 1,
+		"logs": {
+			"enabled": true,
+			"head_sampling_rate": 1,
+			"persist": true,
+			"invocation_logs": true
+		},
+		"traces": {
+			"enabled": true,
+			"persist": true,
+			"head_sampling_rate": 1
+		}
 	}
 	// Secrets (set via `wrangler secret put`):
 	// BOT_TOKEN - Telegram bot token