Telegram /news command: net XAU/USD news sentiment score on demand

Owner-locked /news replies with the existing get_pair_sentiment() net
score (XAU mean - USD mean, -1..+1) and its label; a caveat line marks
the no-headlines case so a feed outage can't read as neutral. Fetch runs
in the shared executor with a placeholder-then-edit reply. Display-only:
news still never gates signals. Registered in handler block, command
menu, help text, docstring, and user guide; 3 new builder tests (299).

Claude-Session: https://claude.ai/code/session_017975c1TufZ3xRYAq8iWTCS

docs/user_guide.html

@@ -130,6 +130,7 @@
 <tr><td><code>/scan</code></td><td>Run an immediate analysis of the primary timeframe.</td></tr>
 <tr><td><code>/autoscan</code></td><td>Toggle automatic scanning (M5 / M15 / H1 / H4 at each candle close).</td></tr>
 <tr><td><code>/status</code></td><td>Uptime, auto-scan state, WebSocket price-monitor state.</td></tr>
+<tr><td><code>/news</code></td><td>Net XAU/USD news sentiment score (informational only — never gates signals).</td></tr>
 <tr><td><code>/cache</code> · <code>/clearcache</code></td><td>Inspect / reset the market-data cache.</td></tr>
 <tr><td><code>/help</code></td><td>Command reference.</td></tr>
 </table>