fix(ci): remove three workflows that never parse (startup_failure) (#26)

## Problem

Three workflows on `main` fail with `startup_failure` — rejected by
Actions at
parse time, so **zero steps run**. They are identifiable because GitHub
names the
run after the *file path* rather than the workflow's `name:`:

```
failure   .github/workflows/rsr-antipattern.yml
failure   .github/workflows/boj-build.yml
failure   .github/workflows/e2e.yml
```

Note `gh pr checks` does **not** surface these — a parse-rejected
workflow
produces no check run at all. Measure with `gh run list --json
name,conclusion`.

## Three independent causes

| Workflow | Root cause |
|---|---|
| `e2e.yml` | `jobs:` present but **every job is commented out** → zero
live jobs → invalid |
| `rsr-antipattern.yml` | calls
`hyperpolymath/standards/.github/workflows/rsr-antipattern-reusable.yml@main`
— the reusable **does not exist** (HTTP 404) |
| `boj-build.yml` | job-level `if:` reads `secrets.BOJ_SERVER_URL`; the
**`secrets` context is unavailable in a job-level `if:`** |

## Why deletion is safe

- `e2e.yml` had **no live jobs**, so no coverage is lost.
- `boj-build.yml` and `rsr-antipattern.yml` **never ran a step**.

No currently-passing gate is affected. All `🔴 Gate:` checks stay green.

## Provenance

Extracted from `fix/consolidate-dogfood-gate` (which also deletes these
three)
so it can land on its own — that branch additionally consolidates the
dogfood
gate and rewrites the Zig/Idris FFI validation, and currently conflicts
with
#22–#24 on six files.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: hyperpolymath