ci: re-trigger after mcpp-index fix (compat qualified names)

chore(mcpp): clean up mcpp.toml + bump to 0.2.2 (#3)

mcpp 0.0.3 inferred-defaults catch up with what we'd been spelling
out by hand:
- `[language]` section is gone — `[package].standard` (default `c++23`)
  + `[build]` knobs cover the same ground.
- `[modules].sources` defaults to `src/**/*.{cppm,cpp,cc,c}` and
  `[modules].exports` is no longer consulted (the modgraph derives
  exports from the actual `export module` declarations).

The dependency block stays the same — mbedtls is still a public
runtime dep — but the comment now points at 0.0.3's transitive
walker as the reason downstream consumers (e.g. mcpplibs.llmapi)
don't need to repeat it.

v0.2.1 — add mcpp build support

* Add mcpp.toml + mcpp.lock for mcpp 0.0.2+ consumers (xmake build path unaffected).
* Drop redundant tests/test_main.cpp; gtest_main provides the entry under mcpp test.

feat: add isCancelled support to download_to_file

Check cancellation callback after each 8KB block during body read.
Allows callers to abort long downloads promptly (e.g. ESC in TUI).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

feat: initial release of mcpplibs-tinyhttps

Minimal C++23 HTTP/HTTPS client library extracted from llmapi.
Features: HTTP client, SSE streaming, proxy support, mbedTLS TLS.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>