chore(release): cut v2.3.0 on the bin-v1.1.3 runtime

- pins the installer, README and INSTALL bootstrap at v2.3.0
- packages/cli/BINARY_RELEASE moves to bin-v1.1.3 so the Go companions
  carry the learn v3 store work; regenerates the five release constant
  files (cli, shared, mcp, shrink, browse)
- CLI package version 1.2.4

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KA6VNr91eQ7MCQAB9E1LVN