The matrix marked every accepted pair with a plain tick, which reads as
"everything works". It does not. ProtocolVersion bumps PATCH for sub-channels a
peer can safely ignore, so Paper 1.3.0 (protocol 1.0.1) against Velocity 1.1.0
(1.0.0) completes the handshake and then silently drops cross-server direct
messages — the very feature that PATCH was bumped for. An operator reading the
tick had no way to learn that, and the pages around it repeated the claim.

The handshake is settled by MAJOR and MINOR alone, so any difference left once a
pair is accepted is a feature the newer end offers and the older will never
answer. Those pairs now carry a warning that says which end lags. Naming the
feature would take a protocol-version-to-feature table on the website, which
would drift from the protocol it describes, so the warning stays general and
leaves the reader one hop from the compatibility page.

The handshake verdict keeps the three checks that mirror Velocity's gate, with
the new one layered after them, so the mirror stays honest. isCompatible now
holds for a degraded pair, which does connect.

Cells are built once per pair in a computed instead of recomputing on each of the
template's reads, which a third state would otherwise have multiplied.

Co-Authored-By: Claude <noreply@anthropic.com>

Several statements were wrong rather than merely thin, and each would have set
the wrong expectation:

- the conversion example implied romaji replaces the input, when the result is
  appended in parentheses and both are sent
- the handshake was described as happening at startup, when it waits for the
  first player to join, so a DISCONNECTED status on an empty server read as a
  fault
- cache eviction was called oldest-first, which the unordered in-memory map
  cannot provide
- the Velocity settings table omitted crossServerDirectMessage
- ConfigManager was described as reading Bukkit's FileConfiguration, and the
  settings storage as recovering from a backup that does not exist

It also documents behaviour that had no mention anywhere: the `!` force-global
prefix, that spy sees channel messages and not only DMs, the nightly build
warnings, the overall 1000ms conversion budget that makes api.timeout above it
ineffective, and the data files the plugin writes.

Co-Authored-By: Claude <noreply@anthropic.com>

Swap the website default locale from Japanese to English.
English now lives at the site root (/), and Japanese moves
under /ja/. Update locale config, nav/sidebar links, internal
doc links, and asset relative paths accordingly.

Co-Authored-By: Claude <noreply@anthropic.com>