#2362 tools: poll the server address the config binds, not loopback (#2330)

Beschreibung

Closes #2330.

`strata_bench.py` starts the server on the config's `host` and then polls readiness at a hardcoded `http://127.0.0.1:<port>` (`tools/strata_bench.py:967`), so a host bound to a specific interface never answers the poll — the report saw the log confirm readiness at `192.168.1.10` while BENCH kept printing "still loading" for 11 minutes.

The change is @Swallowtail23's patch from the report, with the mapping lifted into `server_base` so the test can reach it and nothing else altered: use the configured host, default to loopback when there is none, map the wildcard binds (`0.0.0.0` → `127.0.0.1`, `::` → `::1`) to something connectable, and bracket IPv6 literals. An explicit `--url` still takes precedence.

## Testing

`python -m unittest tools.test_bench_host` — five cases: a configured LAN host, an absent host, both wildcards, a bare and an already-bracketed IPv6 literal, and a hostname. Replacing the mapping with the old hardcoded `127.0.0.1` fails four of them, so they are guards rather than restatements.