Add bootc-compatible labels to container-encapsulate

- Implement complete bootc label support for apt-ostree compose container-encapsulate
- Add containers.bootc, ostree.bootable, ostree.commit, ostree.linux, aptostree.inputhash labels
- Add smart kernel version detection from OSTree tree structure
- Fix container-encapsulate command routing and argument parsing
- Update CHANGELOG.md with bootc label documentation

This enables full compatibility with bootc-image-builder and the broader bootc ecosystem.

target-ci/.rustc_info.json

@@ -0,0 +1 @@
+{"rustc_fingerprint":5697332904451019182,"outputs":{"17747080675513052775":{"success":true,"status":"","code":0,"stdout":"rustc 1.89.0 (29483883e 2025-08-04)\nbinary: rustc\ncommit-hash: 29483883eed69d5fb4db01964cdf2af4d86e9cb2\ncommit-date: 2025-08-04\nhost: x86_64-unknown-linux-gnu\nrelease: 1.89.0\nLLVM version: 20.1.7\n","stderr":""},"205422932214705274":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n/home/joe/.rustup/toolchains/stable-x86_64-unknown-linux-gnu\noff\npacked\nunpacked\n___\npanic=\"unwind\"\nproc_macro\ntarget_abi=\"\"\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"gnu\"\ntarget_family=\"unix\"\ntarget_feature=\"adx\"\ntarget_feature=\"aes\"\ntarget_feature=\"avx\"\ntarget_feature=\"avx2\"\ntarget_feature=\"avxvnni\"\ntarget_feature=\"bmi1\"\ntarget_feature=\"bmi2\"\ntarget_feature=\"cmpxchg16b\"\ntarget_feature=\"f16c\"\ntarget_feature=\"fma\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"gfni\"\ntarget_feature=\"lzcnt\"\ntarget_feature=\"movbe\"\ntarget_feature=\"pclmulqdq\"\ntarget_feature=\"popcnt\"\ntarget_feature=\"rdrand\"\ntarget_feature=\"rdseed\"\ntarget_feature=\"sha\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_feature=\"sse3\"\ntarget_feature=\"sse4.1\"\ntarget_feature=\"sse4.2\"\ntarget_feature=\"ssse3\"\ntarget_feature=\"vaes\"\ntarget_feature=\"vpclmulqdq\"\ntarget_feature=\"xsave\"\ntarget_feature=\"xsavec\"\ntarget_feature=\"xsaveopt\"\ntarget_feature=\"xsaves\"\ntarget_has_atomic=\"16\"\ntarget_has_atomic=\"32\"\ntarget_has_atomic=\"64\"\ntarget_has_atomic=\"8\"\ntarget_has_atomic=\"ptr\"\ntarget_os=\"linux\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"unknown\"\nunix\n","stderr":""}},"successes":{}}