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.

5 files changed, 98 insertions, 22 deletions

diff --git a/examples/example-combine-pathf-dispatch-tree/Cargo.lock b/examples/example-combine-pathf-dispatch-tree/Cargo.lock
index 9fdbf4f..3603db8 100644
--- a/examples/example-combine-pathf-dispatch-tree/Cargo.lock
+++ b/examples/example-combine-pathf-dispatch-tree/Cargo.lock
@@ -3,6 +3,39 @@
 version = 4
 
 [[package]]
+name = "camino"
+version = "1.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb1307f12aa967b5a58416e87b3653360e0fd614a016b6e970db08fecbb1b80d"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "cargo-platform"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd0061da739915fae12ea00e16397555ed4371a6bb285431aab930f61b0aa4ba"
+dependencies = [
+ "serde",
+ "serde_core",
+]
+
+[[package]]
+name = "cargo_metadata"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef987d17b0a113becdd19d3d0022d04d7ef41f9efe4f3fb63ac44ba61df3ade9"
+dependencies = [
+ "camino",
+ "cargo-platform",
+ "semver",
+ "serde",
+ "serde_json",
+ "thiserror",
+]
+
+[[package]]
 name = "equivalent"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -32,6 +65,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "itoa"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
+
+[[package]]
 name = "just_fmt"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -69,7 +108,6 @@ version = "0.5.0"
 dependencies = [
  "just_fmt",
  "might_be_async",
- "mingling_pathf",
 ]
 
 [[package]]
@@ -77,6 +115,7 @@ name = "mingling_macros"
 version = "0.5.0"
 dependencies = [
  "just_fmt",
+ "mingling_pathf",
  "proc-macro2",
  "quote",
  "syn 2.0.118",
@@ -86,6 +125,7 @@ dependencies = [
 name = "mingling_pathf"
 version = "0.5.0"
 dependencies = [
+ "cargo_metadata",
  "just_fmt",
  "proc-macro2",
  "syn 2.0.118",
@@ -110,12 +150,23 @@ dependencies = [
 ]
 
 [[package]]
+name = "semver"
+version = "1.0.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a7852d02fc848982e0c167ef163aaff9cd91dc640ba85e263cb1ce46fae51cd"
+dependencies = [
+ "serde",
+ "serde_core",
+]
+
+[[package]]
 name = "serde"
 version = "1.0.229"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4148590afebada386688f18773da617792bf2ef03ffc1e4cbd2b1d45b023e0ba"
 dependencies = [
  "serde_core",
+ "serde_derive",
 ]
 
 [[package]]
@@ -139,6 +190,19 @@ dependencies = [
 ]
 
 [[package]]
+name = "serde_json"
+version = "1.0.151"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c841b55ecdae098c80dcae9cf767f6f8a0c2cdb3416bbef72181df4d0fe73f14"
+dependencies = [
+ "itoa",
+ "memchr",
+ "serde",
+ "serde_core",
+ "zmij",
+]
+
+[[package]]
 name = "serde_spanned"
 version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -170,6 +234,26 @@ dependencies = [
 ]
 
 [[package]]
+name = "thiserror"
+version = "2.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec86235f5fcc2a73650310756d2ac5b138a5780bbbdfae3eeccec992c435ba4f"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc04cd3e1236dd4a98afca4569f2deb3f120e5422a4023be2cb683f8486292af"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.3",
+]
+
+[[package]]
 name = "toml"
 version = "0.8.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -224,3 +308,9 @@ checksum = "df79d97927682d2fd8adb29682d1140b343be4ac0f08fd68b7765d9c059d3945"
 dependencies = [
  "memchr",
 ]
+
+[[package]]
+name = "zmij"
+version = "1.0.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29666d0abbfad1e3dc4dcf6144730dd3a3ab225bbbdac83319345b1b44ccfc1b"
diff --git a/examples/example-combine-pathf-dispatch-tree/Cargo.toml b/examples/example-combine-pathf-dispatch-tree/Cargo.toml
index 2c866f7..6fcfc48 100644
--- a/examples/example-combine-pathf-dispatch-tree/Cargo.toml
+++ b/examples/example-combine-pathf-dispatch-tree/Cargo.toml
@@ -10,17 +10,4 @@ mingling = { path = "../../mingling", features = [
     "pathf",
 ] }
 
-[build-dependencies]
-mingling = { path = "../../mingling", features = [
-    "builds",
-
-    # --------- IMPORTANT ---------
-    # To use pathf under dispatch_tree
-    #   **must** enable the `dispatch_tree`
-    #   feature in build dependencies
-    "dispatch_tree",
-    "pathf",
-    # --------- IMPORTANT ---------
-] }
-
 [workspace]
diff --git a/examples/example-combine-pathf-dispatch-tree/build.rs b/examples/example-combine-pathf-dispatch-tree/build.rs
deleted file mode 100644
index d909431..0000000
--- a/examples/example-combine-pathf-dispatch-tree/build.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-fn main() {
-    mingling::build::analyze_and_build_type_mapping().unwrap();
-}
diff --git a/examples/example-combine-pathf-dispatch-tree/page.toml b/examples/example-combine-pathf-dispatch-tree/page.toml
index 88557af..b4e64e9 100644
--- a/examples/example-combine-pathf-dispatch-tree/page.toml
+++ b/examples/example-combine-pathf-dispatch-tree/page.toml
@@ -6,5 +6,5 @@ category = "advanced"
 desc = """
 Demonstrates combining the `pathf` and `dispatch_tree` features. Types are defined in submodules and automatically resolved. Requires `dispatch_tree` in both `[dependencies]` and `[build-dependencies]`.
 """
-tags = ["pathf", "dispatch_tree", "extras", "build.rs"]
-files = ["src/main.rs", "src/sub/mod.rs", "build.rs", "Cargo.toml"]
+tags = ["pathf", "dispatch_tree", "extras"]
+files = ["src/main.rs", "src/sub/mod.rs", "Cargo.toml"]
diff --git a/examples/example-combine-pathf-dispatch-tree/src/main.rs b/examples/example-combine-pathf-dispatch-tree/src/main.rs
index 75888ee..a93e7ae 100644
--- a/examples/example-combine-pathf-dispatch-tree/src/main.rs
+++ b/examples/example-combine-pathf-dispatch-tree/src/main.rs
@@ -4,11 +4,13 @@
 //! > Types are defined in a submodule (`sub`), and `gen_program!()` resolves
 //! > them automatically via pathf without explicit `use` imports.
 //! >
-//! > **Important**: `dispatch_tree` must be enabled in BOTH `[dependencies]`
-//! > AND `[build-dependencies]` so that pathf's builder can detect
-//! > `__internal_dispatcher_*` types needed by the dispatch tree.
+//! > **Important**: `dispatch_tree` must be enabled so that pathf's builder can
+//! > detect `__internal_dispatcher_*` types needed by the dispatch tree.
 //! >
 //! > Also requires `extras` for the implicit `dispatcher!("hello")` form.
+//! >
+//! > With the `pathf` feature, `gen_program!()` automatically invokes
+//! > `build_pathf!()` at compile time — no `build.rs` needed.
 //!
 //! Run:
 //! ```bash