Improves readability and reduces logging verbosity

Removes excessive logging to improve readability and reduce verbosity.
Streamlines balance processing and improves logging for settlement amounts.
Adds a note about Fava's internal normalization behavior to the beancount formatting.

beancount_format.py

@@ -576,6 +576,10 @@ def format_net_settlement_entry(
         Fava API entry dict
     """
     # Build postings for net settlement
+    # Note: We use @@ (total price) syntax for cleaner formatting, but Fava's API
+    # will convert this to @ (per-unit price) with a long decimal when writing to file.
+    # This is Fava's internal normalization behavior and cannot be changed via API.
+    # The accounting is still 100% correct, just not as visually clean.
     postings = [
         {
             "account": payment_account,