fix(news): add duplicate-guard to classifyRetryableError, fix log level and dead code

- Add "already exists|duplicate" guard in classifyRetryableError so a 409
  response indicating a duplicate signal short-circuits before the
  NONCE_CONFLICT branch, preventing costly re-payment retries (mirrors the
  same guard already present in inbox.tools.ts)
- Change console.error() to console.warn() for retry progress/info logs in
  news_file_signal — these are informational, not errors
- Annotate the unreachable post-loop throw as dead code (the loop always
  exits via return on success or throw on the final failed attempt)
- Add createFungiblePostCondition to test-news-file-signal.ts to enforce
  the exact sBTC transfer amount as a post-condition

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tfireubs-ui

src/tools/news.tools.ts

@@ -157,6 +157,15 @@ interface RetryInfo {
 function classifyRetryableError(status: number, body: unknown): RetryInfo {
   const NOT_RETRYABLE: RetryInfo = { retryable: false, delayMs: 0, relaySideConflict: false };
 
+  // Duplicate-signal 409 from the news API must NOT be retried —
+  // the signal was already delivered and retrying would re-pay.
+  if (status === 409) {
+    const bodyStr = typeof body === "string" ? body : JSON.stringify(body);
+    if (/already exists|duplicate/i.test(bodyStr)) {
+      return NOT_RETRYABLE;
+    }
+  }
+
   if (typeof body === "object" && body !== null) {
     const b = body as Record<string, unknown>;
     const rawRetryAfter = typeof b["retryAfter"] === "number" ? b["retryAfter"] : 0;
@@ -719,7 +728,7 @@ Fields:
 
         for (let attempt = 0; attempt < MAX_ATTEMPTS; attempt++) {
           if (attempt > 0 && nextRetryDelayMs > 0) {
-            console.error(
+            console.warn(
               `[news_file_signal] Retry attempt ${attempt}/${MAX_ATTEMPTS - 1} after ${nextRetryDelayMs}ms`
             );
             await sleep(nextRetryDelayMs);
@@ -803,7 +812,7 @@ Fields:
           const retry = classifyRetryableError(finalRes.status, parsed);
 
           if (retry.retryable && attempt < MAX_ATTEMPTS - 1) {
-            console.error(
+            console.warn(
               `[news_file_signal] Retryable error on attempt ${attempt + 1}: status=${finalRes.status} relaySide=${retry.relaySideConflict} body=${responseData}`
             );
             nextRetryDelayMs = retry.delayMs;
@@ -824,6 +833,8 @@ Fields:
           );
         }
 
+        // Dead code: the loop always exits via return (success) or throw (failure above).
+        // This path is only reached if MAX_ATTEMPTS is 0, which is not a valid config.
         throw new Error(
           `Signal filing failed after ${MAX_ATTEMPTS} attempts. Last error: ${lastError}`
         );

tests/scripts/test-news-file-signal.ts

@@ -29,6 +29,7 @@ import { getWalletManager } from "../../src/services/wallet-manager.js";
 import { getAccount, NETWORK, checkSufficientBalance } from "../../src/services/x402.service.js";
 import { getStacksNetwork } from "../../src/config/networks.js";
 import { getContracts, parseContractId } from "../../src/config/contracts.js";
+import { createFungiblePostCondition } from "../../src/transactions/post-conditions.js";
 import { bip322Sign } from "../../src/utils/bip322.js";
 
 const SIGNALS_URL = process.env.SIGNALS_URL || "http://localhost:8787/api/signals";
@@ -180,6 +181,13 @@ async function main() {
   console.log("\n[6] Building sponsored tx...");
   const contracts = getContracts(NETWORK);
   const { address: contractAddress, name: contractName } = parseContractId(contracts.SBTC_TOKEN);
+  const postCondition = createFungiblePostCondition(
+    account.address,
+    contracts.SBTC_TOKEN,
+    "sbtc-token",
+    "eq",
+    amount
+  );
   const transaction = await makeContractCall({
     contractAddress,
     contractName,
@@ -192,6 +200,7 @@ async function main() {
     ],
     senderKey: account.privateKey,
     network: getStacksNetwork(NETWORK),
+    postConditions: [postCondition],
     sponsored: true,
     fee: 0n,
   });