Add a new `test-all` command that runs tests across all crates with
optional per-crate command overrides via `mingling-ci.toml` files.

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.

Remove the `pack!`, `pack_err!`, `pack_structural!`, and
`pack_err_structural!` macros, replacing all pipeline type definitions
with `#[derive(Grouped)]` and `#[derive(Grouped, Wrap)]` attributes.
This changes the generated struct shape from named-field structs with an
`inner` field to tuple structs accessed via `.0`, and removes the
auto-generated `name` and `info` fields from error types.

The `dispatcher!` macro no longer requires a `CMD*` dispatcher type
argument; the dispatcher struct is now generated internally as
`__Dispatcher{Pascal}`. The `Node` type, `node!` macro, and
`Dispatcher::node()` / `clone_dispatcher()` methods are removed.

Dispatchers are now always registered at compile time, removing the
`with_dispatcher` / `with_dispatchers` methods and the
`PathfinderConfig` API. The `dispatch_tree` feature now only controls
the matching strategy (trie vs linear list).

Mark all source files with a comment indicating they are not optimized
for documentation purposes.

- Add `#[must_use]` to public constructors and getters
- Change `init_with_config` to accept `&PathfinderConfig` instead of
  owned value
- Refactor `map_or_else` and `or_insert_with` for clippy compliance
- Add `#![deny(clippy::pedantic)]` and `#![deny(clippy::nursery)]`
- Document error cases in public API docs
- Simplify duplicated dispatcher_clap analysis logic

Remove the BasicStructPattern from pathf's pattern analyzer to eliminate
noise from plain structs not associated with any Mingling macro.

Also clean up the now-unused `basic_struct` module and update the
integration test to assert plain structs are no longer collected.