wallet: clear message when the node's protocol is incompatible (#713)

[vsnation]

Fix: when the node rejects the wallet as incompatible (a protocol or consensus mismatch), the CLI and wallet-api say so and tell the user to update, instead of "please check your network" (CLI) or nothing (wallet-api).

Why: NodeProtocolIncompatible was only mapped to a message in the UI client. CliNodeConnection::OnConnectionFailed printed the generic Connection Failed - Please check your network, and wallet-api's NodeNetwork::OnConnectionFailed logged nothing (#713, CLI/API part; the UI part belongs to beam-ui).

How to see the bug (master, local only)

beam-node --port=31401 --TreasuryChecksum=0 &          # a node with different consensus rules
beam-wallet restore --pass=p --wallet_path=w.db --seed_phrase="abandon;abandon;abandon;abandon;abandon;abandon;abandon;abandon;abandon;abandon;abandon;about;"
beam-wallet listen --pass=p --wallet_path=w.db -n 127.0.0.1:31401
# master: "Connection Failed - Please check your network reason: Incompatible peer cfgs: …"
wallet-api --pass=p --wallet_path=w.db -n 127.0.0.1:31401 -p 10000
# master: nothing about it in the console or logs/api_*.log

Improvement

	master	this PR
beam-wallet listen	Connection Failed - Please check your network reason: Incompatible peer cfgs: …	The node uses an incompatible protocol version. If the network has been upgraded, please update your wallet to the latest version. reason: Incompatible peer cfgs: …
wallet-api	(nothing logged)	the same message
other connection failures	generic message	unchanged

"Incompatible" rather than "newer": the same error is raised for an older node ("Legacy"). The message repeats on reconnect attempts, like the old one.

Testing: both rows above, with master's and this branch's binaries against a local node with different consensus rules. Fork CI (running): https://github.com/vsnation/beam/actions/runs/37480560296

Fixes #713