Add futures_quote tool: CBOT price + change since open + on day

New futures_quote(commodity, delivery?) tool wraps the new /api/data/futures
endpoint: reports latest price, today's session open, prior settle, and both
moves (since open and on the day). With a delivery month it resolves the listed
contract; without it, the continuous nearby. Adds client.futures(), fmt_futures(),
tests, and a CHANGELOG entry.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ag_bids_mcp/server.py

@@ -64,6 +64,31 @@ def best_local_bid(
         return fmt.fmt_best(commodity, payload)
 
 
+@mcp.tool()
+def futures_quote(
+    commodity: Annotated[
+        str, Field(description="Grain: 'corn', 'soy' (soybeans), or 'wheat'.")
+    ],
+    delivery: Annotated[
+        str | None,
+        Field(description="Delivery month (e.g. 'Jul 2026') to resolve the listed "
+                          "contract. Omit for the continuous nearby."),
+    ] = None,
+) -> str:
+    """CBOT futures price and change for a commodity (optionally one delivery month).
+
+    Reports the latest price, today's session open, the prior day's close, and
+    both moves: change since the open and change on the day (vs the previous
+    settle). With `delivery` it resolves the listed contract that month prices
+    against; without it, the continuous nearby."""
+    cm = commodity.strip().lower()
+    with track("futures_quote", commodity=cm, delivery=delivery):
+        if cm not in VALID_GRAIN:
+            return f"`commodity` must be one of: {sorted(VALID_GRAIN)}"
+        payload = client.futures(commodity=cm, delivery=delivery)
+        return fmt.fmt_futures(payload)
+
+
 @mcp.tool()
 def current_lime_price() -> str:
     """Latest lime prices on file across all sources. Lime is rarely posted on