Initial commit: move CLI (milestone 2)

- src/move.ts entry point with CLI parsing, --help, --version
- src/cli.ts: parseCliArgs, printHelp, ParsedCliArgs, CliError, VERSION
- src/config.ts: Config type, DEFAULT_CONFIG, resolveConfig
- src/keeper.ts: synthetic-activity sweep + idle-watch loop
- package.json bin entry + shebang for 'bun link' global install
- install.sh: contributor bootstrap (will be repurposed; see
  DISTRIBUTION-PLAN.md for the end-user installer design)
- DISTRIBUTION-PLAN.md captures the tabled end-user distribution work

.gitignore

@@ -0,0 +1,9 @@
+node_modules/
+
+# Logs
+*.log
+
+# OS / editor cruft
+.DS_Store
+.vscode/
+.idea/