v0.11.0

SUCO 0.11.0 — real projects build on the grid again

Fixed
- The header-set split produced two halves that cannot be reassembled into a
  well-formed translation unit, so any project with a realistic header set
  failed to compile remotely, and failed the build outright. Now gated (it
  never actually was) and off by default. SUCO builds itself through the grid
  at 1.54x over a local -j8.
- An unreachable coordinator cost ~3 minutes per TU instead of one second.
  A circuit breaker now fails fast: 181s -> 8s.

Added
- Per-job target OS on the dashboard (Windows cross-compile vs native Linux).
- A Windows installer published alongside the release zip.
- A reproducible grid benchmark with methodology and caveats.