v3.1.1

i18n infrastructure release. Memory Bank now ships locale-aware
.memory-bank/ template bundles. Existing English users are unaffected —
this is a pure capability addition.

Added

• Locale template bundles under templates/locales/{en,ru,es,zh}/.memory-bank/.
  en and ru ship as full translations; es and zh ship as scaffolds
  (EN copy + TODO(i18n-<lang>) banner) that the community can complete via
  PR — see docs/i18n.md.
• New scripts/mb-config.sh — 4-tier locale resolver:
  1. MB_LANG env var
  2. $MB_ROOT/.memory-bank/.mb-config (lang=XX)
  3. Heuristic auto-detect from existing bank content (Cyrillic → ru) with
     write-back for determinism
  4. Default en
• New scripts/mb-init-bank.sh — deterministic, locale-aware bank
  scaffolder. Respects --lang=XX, MB_LANG, existing .mb-config; never
  overwrites user-authored files.
• memory-bank init --lang=XX CLI flag and /mb init --lang=XX
  command form.
• install.sh --language {en|ru|es|zh} — expanded whitelist (was en|ru).
• docs/i18n.md — contributor guide for adding a new locale.

Contract

• Canonical English anchors (<!-- mb-active-plans -->,
  <!-- mb-recent-done -->, ## Ideas, ## ADR) remain English in every
  locale bundle — every mb-* script depends on them.
• commands/mb.md, script CLI output, and the main English docs stay English.

Coverage

• 216 pytest + 14 skipped (pytest suite)
• 14/14 mb-config bats
• 9/9 mb-init-bank bats
• 28/28 install/uninstall e2e bats