refactor!: replace build.rs with compile-time macro build steps

BREAKING CHANGE: Replace the `build`/`builds` feature system with
compile-time macro-driven generation. `gen_program!()` now automatically
invokes `build_comp!()` and `build_pathf!()` when the `comp`/`pathf`
features are enabled, eliminating the need for `build.rs` and
`[build-dependencies]` blocks.

This removes the `build` feature, the `mingling::build` module, and all
related build-time API functions. Completion scripts are now written to
`{target_directory}/mingling/` instead of `target/release/`. The
`mingling_cli` uses `build_comp!("mling")` for its custom binary name.

1 files changed, 8 insertions, 2 deletions

diff --git a/mingling_macros/Cargo.toml b/mingling_macros/Cargo.toml
index 137213a..6ae7aeb 100644
--- a/mingling_macros/Cargo.toml
+++ b/mingling_macros/Cargo.toml
@@ -19,11 +19,11 @@ default = []
 async = []
 
 clap = []
-comp = []
+comp = ["dep:just_template", "dep:mingling_pathf"]
 dispatch_tree = []
 structural_renderer = []
 repl = []
-pathf = []
+pathf = ["dep:mingling_pathf"]
 
 extras = []
 
@@ -33,3 +33,9 @@ quote.workspace = true
 proc-macro2.workspace = true
 
 just_fmt.workspace = true
+
+# comp — compile-time completion script generation (build_comp!())
+just_template = { workspace = true, optional = true }
+
+# pathf — compile-time type path analysis (build_pathf!())
+mingling_pathf = { workspace = true, optional = true }