refactor(rust): remove resolved borrowck-reshape comments (bucket A, 256 sites) - #35360

Same class as the two `jsc_hooks.rs` sites 9f71d47 dropped, but the sweep missed `load_preloads`: the new `// SAFETY:` at 670-671 is followed by a blank line so it guards no `unsafe` block, and the first unsafe (line 675) already has its own `// SAFETY: per fn contract` (674). It escaped the earlier grep only because a blank line + section-header comment separates the two SAFETY headers rather than stacking them directly. Same fix as 9f71d47: drop 670-671 (or fold the reentrancy note into the fn

Two more A1 deletions drop the caller-side "the slab does not reallocate/resize for the duration of this loop" invariant at `Slice<T>` snapshot sites — `LinkerContext.rs:560` and `bundle_v2.rs:1900` (`find_reachable_files`). This is the same borrowck-cannot-enforce class already restored at ParseTask/IOReader/IOWriter in 6bcc8c2 (`slice()` takes `&self`, so a mid-loop `self.graph.ast.append(…)` would compile and dangle the raw column pointers), and it also leaves `bundle_v2.rs:5114` ("Mirrors th