22335474d7 net: format peer+addr logs with `LogPeer` (Lőrinc)
e55ea534f7 test: add pre-`LogPeer` net log assertion (Lőrinc)
736b17c0f0 log: fix minor formatting in debug logs (Lőrinc)
9cf82bed32 log: show placeholders for missing peer fields (Lőrinc)
Pull request description:
This is an alternative to #34293, but aims to address the remaining logging inconsistencies more broadly.
It extends the example fixed there to every instance, restores the original separator behavior, applies it consistently via a single helper, and adds tests for `logips` (covering both current and new behavior).
### Problem
After #28521 centralized peer address logging into `CNode::LogIP()`, the original comma separator before `peeraddr=` was lost, resulting in inconsistent formatting across net (and recent private broadcast) logs.
Some lines also had double spaces, empty fields, or mismatched format specifiers.
### Fix
Introduces `CNode::LogPeer(bool)` which always emits `peer=<id>` and, when `-logips=1`, appends `, peeraddr=<addr>`. This eliminates hand-rolled separators and makes peer identification predictable.
Minor issues (double spaces, empty placeholders, format specifiers) are fixed along the way in separate commits.
### Reproducer
Run with `-debug=net -logips=1` and observe peer log lines now show `peer=<id>, peeraddr=<addr>` (comma-separated). The new assertion in `feature_logging.py` automates this check.
ACKs for top commit:
naiyoma:
ACK 22335474d7
vasild:
ACK 22335474d7
sedited:
ACK 22335474d7
Tree-SHA512: 562262a58c3042f139099ff4c41e3fc6a97505fe9603c2bf700a97fd0aa052954b47c14da0e50c1fc311db1ae6c04e6a92156c9b85e25c777a637b7766c1dafe
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