feat: add MCP Apps extension substrate #766

Job	Run time
Rust test (Redis-backed paths)	2m 3s
Rust test (macos-latest)	3m 47s
Rust fmt	19s
Build wheels (macos-latest)	1m 42s
Rust test (ubuntu-latest)	2m 44s
Rust build (macos-latest)	3m 14s
Dependency policy	3m 57s
Documentation	1m 31s
Supply-chain vet	1m 58s
Build wheels (ubuntu-latest)	1m 41s
Rust clippy	1m 48s
Benchmarks (build check only)	7m 42s
License check (workspace)	3m 42s
Rust build (ubuntu-latest)	2m 44s
Coverage	3m 45s
Resolve Rust Python release matrix	0s
Release wheels (${{ matrix.platform }})	0s
Release sdist	0s
Publish Rust Python packages	0s
	42m 37s

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