basou: Release v0.69.0 (- reserved for stdin on input-file flags, signal exit codes as the platform's shell reports them, pathless --file read errors, compatibility policy)

[takashi-matsuyama]

Bump-only release PR for v0.69.0: the four package.json versions and the CHANGELOG heading.

Contents, already on main:

• basou: Refuse - as the file of --file, --from-file and --from, reserving it for stdin #351 Refuse - as the file of --file, --from-file and --from, reserving it for stdin (Changed)
• basou: Exit as the platform's shell does when a signal ends the child of exec and run #352 Exit as the platform's shell does when a signal ends the child of exec and run (Fixed)
• docs: Reserve - for stdin, guarantee review record's input shape, and say what a signal's exit code means across platforms #353 compatibility.md: reserve - for stdin, guarantee review record's input shape, say what a signal's exit code means across platforms (Changed)
• basou: Keep the path out of decision capture's and review record's error for a --file they cannot read #354 Keep the path out of decision capture's and review record's error for a --file they cannot read (Fixed)

Minor, as #351 narrows what four existing flags accept.

Verified on a worktree of this commit: pnpm install --frozen-lockfile (lockfile unchanged), pnpm -r build, pnpm typecheck, pnpm lint, pnpm lint:lang, pnpm lint:paths, pnpm test (core 2750, sdk 65, cli 1538) all exit 0; the built CLI reports 0.69.0 (build 2fe0306, ...).