chore(ci): remove un-instantiated e2e.yml (0 jobs, permanently failing)

jobs: is present but every job block is commented out. An empty jobs: map is
invalid, so the run dies with 0 jobs and conclusion=failure on every push that
touches src/**, ffi/** or tests/**. It has never run a test.

Deleted rather than instantiated: blob-SHA comparison against a pure template
clone shows this repo's src/ differs from the scaffold in <=4 files, so there is
no project behaviour to exercise end-to-end. Writing a job anyway would pass
without testing anything -- a fake gate.

Debt: this repo has NO e2e coverage, and this file never provided any.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: hyperpolymath