`examples/ffi-objc-dsl-07-mangling-table.sx` exercises every common
mangling shape in one fixture and pins the resolved selectors via
both `.txt` and `.ir` snapshots:
| sx method | derived selector |
|-----------------------------------|----------------------------|
| `length` | `length` |
| `addObject(o)` | `addObject:` |
| `combine_and(a, b)` | `combine:and:` |
| `insert_after_index(a, b, c)` | `insert:after:index:` |
| `add_observer_for_event(a, b, c, d)` | `add:observer:for:event:` |
| `initWithFrame_options(f, o)` | `initWithFrame:options:` |
| `custom_name #selector("actualSelectorName")` | `actualSelectorName` |
The class is synthesized at runtime via `objc_allocateClassPair` +
`class_addMethod` per selector (mirrors the pattern in
`ffi-objc-dsl-{01..05}.sx`), so the test actually dispatches through
the real Obj-C runtime on macOS.
Single commit because the implementation already shipped in 3.0/3.2;
this is a new regression that locks in current behavior, not a
test-then-make-green pair.
The `.ir` snapshot opts in via the existing run_examples.sh mechanism
(presence of a `.ir` file for the same name triggers capture). The
captured `OBJC_METH_VAR_NAME_*` constants surface every selector
string change at a glance.
166/166 tests.