ci: remove 43 inherited WezTerm upstream workflows

These were carried over from the WezTerm fork and do not apply to
TurtleTerm: platform continuous builds, nix flake, docs/pages pipeline,
Rust fmt, thread-locking bot. All used blocked third-party actions
(dtolnay/*, baptiste0928/*, DeterminateSystems/*, dessant/*) or had
hard-coded 'if: github.repository == wezterm/wezterm' guards making
them no-ops in this repo. They were also generating scheduled
startup_failure noise on every hourly/daily trigger.

Author: mdheller