cc/msvc: build blade-test's cc suites (flag translation, framework deps, private incs)

[chen3feng]

Drives blade-go's MSVC backend (#66) against blade-test's real cc suites on Windows. cc_basic (3/3), cc_incs (1/1), cc_export_map (1/1), cc_dll_export (1/1) now build and their tests pass. Four gaps fixed — all gcc/clang behavior unchanged (branch on IsMSVC()):

1. cc_config gcc-flag translation (mapFlagsToMSVC) — projects write cc_config in gcc syntax and layer MSVC bits in msvc_config. On MSVC, translate -std=c++17→/std:c++17, -O2→/O2, -D/-I→/D//I, -g→/Z7, drop gcc-only -W/-m/-f (mirrors Blade's _map_gcc_flags_to_msvc). Also read msvc_config (append_cppflags, warnings, …) and default /SUBSYSTEM:CONSOLE — without it link.exe can't infer the entry point when main() is only in a static lib (gtest_main/test_main) → LNK1561.
2. Config vocabulary — register the full *_config set (java/scala/go/cuda/lex_yacc/link/coverage/sanitizer/…) so a multi-language BLADE_ROOT loads instead of erroring undefined: java_test_config; blade-go records but ignores the ones it doesn't build.
3. Framework libs as deps — a cc_test/cc_benchmark's gtest_libs/gtest_main_libs are injected as deps by the graph builder, so a //-target framework (blade-test's test_framework), a #syslib, and a thirdparty/<port> vcpkg lib are all classified and linked by the normal transitive path. Replaces the helper that silently dropped //-target frameworks. Verified flare still links libgtest/libgtest_main.
4. Private incs — a target's own attr['incs'] (package-relative private include dirs) now goes on its compiles; cc_incs's incs=['include'] resolves greeting.h.

Tests

mapFlagsToMSVC translation; cc_test framework-dep injection + classification; private incs on the compile path. go test ./... green on macOS/arm64; suites verified on Windows 11 ARM64 (VS2026).

Remaining (separate follow-ups)

cc_asm (BUILD parse + ml64/armasm rule), real DLL output for dynamic_link, cc-check-undefined via dumpbin.