release: bump version to 0.0.16

New in this release:
- Custom [indices] in mcpp.toml with project-level isolation
- Lockfile v2 with index SHA pinning and namespace tracking
- mcpp index pin/unpin CLI commands
- Fetcher routing for custom git and local path indices
- Workspace indices inheritance
- Auto-clone custom index repos on first build
- README redesign with demo GIF, AI onboarding, contributor guide
- Agent skills: mcpp-contributing, mcpp-usage

Author: Sunrisepeak

mcpp.toml

@@ -1,6 +1,6 @@
 [package]
 name        = "mcpp"
-version     = "0.0.15"
+version     = "0.0.16"
 description = "Modern C++ build & package management tool"
 license     = "Apache-2.0"
 authors     = ["mcpp-community"]

src/toolchain/fingerprint.cppm

@@ -18,7 +18,7 @@ import mcpp.toolchain.detect;
 
 export namespace mcpp::toolchain {
 
-inline constexpr std::string_view MCPP_VERSION = "0.0.15";
+inline constexpr std::string_view MCPP_VERSION = "0.0.16";
 
 struct FingerprintInputs {
     Toolchain                       toolchain;