fix: keep v1 colour codes out of the import report and unify the no-homes notice

[milanmalhotra]

Closes #49

Problem

/import-homes sethomes echoed v1 message settings into chat verbatim. v1's own defaults carry section-sign colour codes, so §4 turned the rest of the advice line red (and §k would scramble it), making a successful import report look like it half failed.

Separately, the "you have no homes yet" notice was sent as info from /homes, as a red error from the homes menu, and with a third wording from /list-homes.

Change

• The two v1 message notes go through messageNote(), which shows ChatColor.COLOR_CHAR as &, prints the value once, and appends "(colour codes shown as &; copy the original from plugins/SetHomes/config.yml to keep them)" only when a code was actually present. The exact original stays recoverable from v1's own file.
• The tp-cooldown note says "no v2 equivalent" rather than "no Set Homes Two equivalent".
• One wording and one severity for the no-homes notice: all three call sites read the noHomes config key with UserInfo.NO_HOMES as the default and send it as info. UserError.NO_HOMES is removed, and /list-homes no longer adds a second usage line.

Tests

mvn test: 371 tests, 0 failures, 0 skipped (was 367). New: a §4/§k fixture produces no § in any note and shows &4/&k; a coded message names plugins/SetHomes/config.yml; a plain message is shown as-is with no caveat; /homes, the menu and /list-homes all send the notice without ChatColor.RED, and /list-homes sends exactly one line. Both guards in messageNote() were broken and restored to confirm the tests catch them.