README quick-start uses removed InputRole/OutputRole API; status section and MSVC claim stale

[petlenz]

From the 2026-08-02 full-repo review (finding F-06). All verified.

1. Quick-start does not compile — README.md:55-57 uses InputRole::Strain / OutputRole::Stress; grep -rn 'InputRole\|OutputRole' include/ src/ examples/ = 0 hits. The real API is Role/roles:: with default role args (examples/linear_elasticity.cpp:26). Regenerate the example from a CI-compiled source.
2. Status stale — README.md:34-39 says "Phase A scaffold ... Not yet working: full tensor / tensor-to-scalar visitor coverage, MOOSE Material text templating, history / internal variables". Tensor e2e gates, state variables, spectral lowering, and the J2 family all shipped.
3. MSVC claim wrong and untested — README.md:109 says "MSVC 19.30+", but std::expected (recipe.h:1362) requires MSVC ≥19.33, and MSVC has never been built (not in CI). Either add a windows library-only CI leg or say "untested".
4. While editing: state that installed-package (find_package) consumption is not yet supported (see the install-rules issue).