DEV_INSTRUCTIONS.md mandates ./tests/run_all_tests.sh for PR merge, but that script and 4 other referenced paths no longer exist

## Summary

[DEV_INSTRUCTIONS.md](https://github.com/agentic-community/mcp-gateway-registry/blob/main/DEV_INSTRUCTIONS.md) tells contributors that passing `./tests/run_all_tests.sh` is **REQUIRED** before a PR can merge:

> ### For PR Merge (REQUIRED)
> ```bash
> # Full test suite including production tests
> ./tests/run_all_tests.sh
>
> # All tests must pass (0 failures) before merging
> ```

That script does not exist. It was removed on 2026-01-06 in "Optimize test suite performance from 150s to 30s" (#330, `6877dc29`), but the docs were never updated. A new contributor following DEV_INSTRUCTIONS.md verbatim hits `no such file or directory` on the one step the document marks as mandatory, and has no stated way to satisfy the merge requirement.

## Every broken reference

Checked all paths and commands DEV_INSTRUCTIONS.md cites — 5 of 8 are gone:

| Referenced path | Cited at | Status |
|---|---|---|
| `tests/run_all_tests.sh` | lines 55, 61, 137, 138 | **missing** (deleted in #330) |
| `tests/agent_crud_test.sh` | line 79 | **missing** |
| `tests/run-lob-bot-tests.sh` | line 87 | **missing** |
| `auth_server/scopes.yml` | line 72 | **missing** |
| `tests/TEST_QUICK_REFERENCE.md` | line 70 | **missing** |
| `tests/lob-bot-access-control-testing.md` | line 71 | **missing** |
| `credentials-provider/generate_creds.sh` | lines 52, 78 | exists |
| `keycloak/setup/generate-agent-token.sh` | lines 84–86 | exists |
| `tests/README.md` | line 69 | exists |

The Development Checklist at lines 129–141 is affected too: two of its ten items reference the missing script.

## What replaced it

`.github/workflows/registry-test.yml` shows the current entrypoint is `scripts/test.py`, which is not mentioned anywhere in DEV_INSTRUCTIONS.md or CONTRIBUTING.md:

```yaml
- run: uv sync --extra dev
- run: uv run python scripts/test.py check
- run: uv run python scripts/test.py coverage -n 8
```

`scripts/test.py` accepts: `check`, `unit`, `integration`, `e2e`, `fast`, `full`, `coverage`, `auth`, `servers`, `search`, `health`, `core`.

I verified both CI commands work locally on a clean tree:

```
$ uv run python scripts/test.py check
✅ All dependencies installed!

$ uv run python scripts/test.py coverage -n 8
6687 passed, 56 skipped, 386 warnings in 41.07s
Required test coverage of 35% reached. Total coverage: 66.10%
✅ Running Tests with Coverage - PASSED
```

Note `--extra dev` is required: without it `scripts/test.py check` fails on missing `freezegun`. `freezegun` is declared under `[project.optional-dependencies] dev`, so a plain `uv sync` does not install it.

## Suggested fix

Replace the two test blocks in DEV_INSTRUCTIONS.md with the commands CI actually runs, so local and CI results agree:

```bash
# one-time
uv sync --extra dev

# fast iteration
uv run python scripts/test.py fast

# before opening a PR (mirrors CI)
uv run python scripts/test.py check
uv run python scripts/test.py coverage -n 8
```

Also worth flagging: the `-n 8` from CI emits `WARNING: Running with 8 workers may cause OOM on EC2`, so the docs may want a lower worker count for local runs.

The four missing non-script references (`auth_server/scopes.yml`, `tests/TEST_QUICK_REFERENCE.md`, `tests/lob-bot-access-control-testing.md`, and the two LOB/CRUD shell scripts) need either updated paths or removal — I could not locate current equivalents, so I have not guessed at replacements.

I am happy to open a PR for the DEV_INSTRUCTIONS.md rewrite if you confirm `scripts/test.py` is the intended contributor-facing entrypoint, and can point me at where the LOB access-control docs moved.

## Environment

- macOS 15 (Darwin 25.5.0), Python 3.14.6, uv 0.12.0
- Verified against `main` at `1cead11d`