feat(pkgs): opencv 0.0.9 单仓库形态 + mcpp 0.0.102 floor (windows scan-deps #261 + module PCM baseline) (#111)

* feat(pkgs): opencv 0.0.7 单仓库形态 — 内置 OpenCV 5 源码构建,退役 compat.opencv

opencv-m 自 0.0.7 起把 OpenCV 5.0.0 的完整源码构建收入自身仓库:上游源码
(third_party/opencv-5.0.0/,官方 tag 的裁剪导入,sha256 锁定,零补丁)与各平台
冻结的 configure 快照(gen/)随 release tarball 一并分发,消费端不执行 CMake。
索引侧因此只保留指向该 release 的 Form A 描述符。

- pkgs/o/opencv.lua:0.0.7(GLOBAL GitHub tag tarball + CN gitcode 镜像,
  两者字节一致,sha256 a896d08d…);描述符注释重写为单仓库形态。仅保留 0.0.7,
  0.0.6 及更早版本随 compat.opencv 一并移除。
- 删除 pkgs/c/compat.opencv.lua、pkgs/c/compat.opencv-unifont.lua 与
  tools/compat-opencv/(描述符生成流水线),以及两个临时快照采集 workflow
  (snapshot-{macos,windows}-opencv.yml)。
- 删除仅用于验证 compat.opencv 的 workspace 成员:opencv、opencv-win、
  opencv-unifont、opencv-dnn;模块层成员 opencv-module{,-dnn,-unifont}
  依赖上调至 0.0.7 并更新已失效的注释(不再有 feature 转发与 linux-only)。
- README 与 validate.yml 的相关描述同步更新。

opencv-m 侧五条 CI 腿(linux gcc/llvm22/musl-static、macOS llvm、windows llvm)
全部通过;本地已用本检出解析 opencv 0.0.7 并运行 opencv-module 成员验证。

* fixup: opencv 0.0.7 → 0.0.8 (template stderr fix; sha256 re-pinned)

v0.0.7's --template opencv scaffold used std::println(stderr, …) under a
bare `import std;` and did not compile (modules do not export the <cstdio>
stderr macro). opencv-m v0.0.8 fixes the template and adds a CI lint for the
class. No library-source or ABI change from 0.0.7.

- pkgs/o/opencv.lua: version 0.0.7 → 0.0.8 (all three OS blocks), sha256
  re-pinned to 0025f7a6…45cd8 (GLOBAL github archive == CN gitcode asset,
  both verified 11756053 bytes). Requires-mcpp note raised to >= 0.0.102
  (windows scan-deps cmdline, mcpp#261).
- tests/examples/opencv-module{,-dnn,-unifont}: consumer pins → 0.0.8.

* ci: mcpp 0.0.101 -> 0.0.102 (windows scan-deps cmdline ceiling, mcpp#261)

The windows workspace leg builds a package's own TUs from under the
registry's xpkgs path (~124 chars) rather than a ~23-char checkout, so
the clang scan-deps command — wrapped in `cmd /c` only to redirect its
P1689 JSON — crossed cmd.exe's 8191-char ceiling on the vendored-opencv
consumer (opencv-module{,-dnn}). mcpp 0.0.102 drops the wrapper via
clang-scan-deps -o and extends #247's response-file fallback to every
$local_includes rule, restoring the CreateProcess 32767 ceiling.

Bump min_mcpp/latest_mcpp together with the CI pin per the index.toml
version-contract rule. Also carries #257 (Clang purview-include depfile),
#258 (OS-conditional [build].flags) and #254 (per-OS splice on target).

* fixup: opencv 0.0.8 → 0.0.9 (module-interface baseline PCM fix; sha256 re-pinned)

0.0.8 was not usable as a windows/clang dependency: opencv's SSE3 baseline
-msse3 tagged the module-interface BMIs, and a baseline consumer TU could not
load opencv.<mod>.pcm (clang -Wmodule-file-config-mismatch). opencv-m v0.0.9
moves -msse3 to a per-glob on the library TUs only, so the interfaces are
baseline-loadable. No public C++ API change.

- pkgs/o/opencv.lua: 0.0.8 → 0.0.9 (all three OS blocks), sha256 re-pinned to
  888c45ad…768a (GLOBAL github archive == CN gitcode asset, both 11756394 bytes).
- tests/examples/opencv-module{,-dnn,-unifont}: consumer pins → 0.0.9.

Author: Sunrisepeak