fields

Declare `Grouped` as `unsafe trait` to make its soundness invariant
visible.
Make `AnyOutput.type_id` and `member_id` private; add public accessors
and
the `unsafe fn new_bare` constructor.

pipeline error routing

Add `AnalyzeItem::foreign()` and `AnalyzeItem::local()` constructors to
distinguish items resolved via `use` imports from local definitions.
Update `GroupPattern` to collect use imports at file and module levels,
resolving `group!(TypeName)` against them.  Migrate all pattern
implementations to use the new constructors, and adjust
`type_mapping_builder` to skip the file's own module prefix for foreign
items.

Make `StructuralData` and `StructuralDataSealed` generic over a program
collector type to bypass the orphan rule for `group_structural!`. This
enables external types to implement `StructuralData<crate::ThisProgram>`
without violating coherence.

patterns

Implement `RenderResult::append_other()` to merge buffered content and
immediate output behavior from one result into another. Add the
`r_append!` macro with both explicit buffer (`dst, src`) and implicit
buffer (`src`) usage forms, re-exported from `mingling::prelude`.

Enables method chaining for `with_resource`, `with_dispatcher`,
`with_dispatchers`, `with_hook`, and `with_setup`