Fix escaped quotes in local server start help

[sdairs]

Summary

• render normal quotes around default in local server start --help
• pin the exact argument help line and reject escaped quote rendering

Tests

• cargo test -p clickhousectl server_start_help_renders_default_name_without_escaped_quotes
• cargo test -p clickhousectl local::cli::tests
• cargo fmt --all --check
• cargo clippy -p clickhousectl --all-targets -- -D warnings

Closes #476

[sdairs]

Carry-over review from PR #482 (old PR for #476). Functionally identical one-line fix; this PR's test is marginally stronger (asserts ErrorKind::DisplayHelp and matches the help line exactly rather than contains). No sdairs review comments existed on #482 (only an external LGTM). No changes required.

One note: local postgres edge cases fails on this branch, but the identical failure exists on its base branch — inherited from the stack base (#547 script drift), not from this diff which touches only a help string and a unit test. Should go green once #547's script update lands and the stack rebases.