Reads session data from OpenCode's SQLite databases at
~/.local/share/opencode/. Reuses the existing better-sqlite3
adapter (same as Cursor), lazy-loaded so users without OpenCode
see no difference. Adds bashCommands to the provider interface
so shell command breakdowns work across all providers.
31 tests, schema validation, diagnostic stderr on failures.
Also fixes a pre-existing tsc error in currency.ts.
