feat: add repo planning/binary repo support and Meson build integration

- add repos.toml source/binary repo configuration with arch overrides and priorities
- add dependency planner/execution plan flow with interactive provider selection and --yes support
- expand binary repo DB metadata (sha512, dependencies, file lists) and repo owns/search helpers
- add rootfs-scoped fd locking and minisign detached signing/verification helpers
- add Meson build/test support for the project with builddir-local CARGO_HOME/CARGO_TARGET_DIR
- install contrib example configs into sysconfdir (/etc/depot.d layout) via Meson
- improve builder env handling (sanitized PATH, tool env passthrough, CXXFLAGS support)
- support += appends in package specs and add build.flags.cxxflags parsing
- prompt for git credentials when private repo auth is required
- update docs/examples and dependency setup (system libs, zstdmt, tempfile pin)

Cargo.toml

@@ -11,19 +11,19 @@ anyhow = "1.0.102"
 ar = "0.9.0"
 bzip2 = "0.6.1"
 clap = { version = "4.5.60", features = ["derive"] }
-flate2 = { version = "1.1.9", default-features = false, features = ["miniz_oxide"] }
+flate2 = "1.1.9"
 git2 = { version = "0.20.4", features = ["vendored-libgit2"] }
 indicatif = "0.18.4"
 nix = { version = "0.31.1", features = ["user"] }
-reqwest = { version = "0.13.2", features = ["blocking", "rustls"] }
-rusqlite = { version = "0.38.0", features = ["bundled"] }
-openssl-sys = { version = "0.9", features = ["vendored"] }
+reqwest = { version = "0.13.2", features = ["blocking", "native-tls"] }
+rusqlite = "0.38.0"
+openssl-sys = "0.9.111"
 semver = "1.0.27"
 serde = { version = "1.0.228", features = ["derive"] }
 yaml-rust2 = "0.11.0"
 sha2 = "0.10.9"
 tar = "0.4.44"
-tempfile = "3.25.0"
+tempfile = "=3.25.0"
 thiserror = "2.0.18"
 toml = "0.9.8"
 url = "2.5.8"
@@ -31,18 +31,13 @@ walkdir = "2.5.0"
 xz2 = "0.1.7"
 zip = "8.1.0"
 zstd = { version = "0.13.3", features = ["zstdmt"] }
-libz-sys = { version = "1.1.23", default-features = false, features = ["stock-zlib", "static"] }
-inquire = "0.9.3"
+libz-sys = "1.1.24"
+inquire = "0.9.4"
 md5 = "0.8.0"
 suppaftp = "8.0.2"
+minisign = "0.8.0"
+petgraph = "0.8.3"
+fd-lock = "4.0.4"
 
 [dev-dependencies]
-tempfile = "3.25.0"
-
-[profile.release]
-opt-level = 3            
-lto = "thin"               
-codegen-units = 1          
-panic = "abort"            
-strip = "symbols"         
-debug = false              
+tempfile = "=3.25.0"