chore(hypatia): delete dead ci-templates/mirror.yml, qualify echidnabot paths, baseline → JCS [stack 2/3] (#433)

## Summary

Stack 2 of 3. It sits on #432, so its diff is commits `96e919c` and
`0850e4a`. It fixes `governance / Validate Hypatia Baseline`, which is
red on `main` with six findings introduced by #426 and #427. The fixes
are made at the source, not by baselining. It also brings
`.hypatia-baseline.json` to the estate format standard: JCS-canonical
I-JSON.

## Changes

- **Deleted `echidna-playground/ci-templates/mirror.yml`** (finding:
`download_then_run_shell`, `curl -sSf https://radicle.xyz/install |
sh`).
- The template never ran: GitHub reads only root workflows (see
`ci-templates/README.adoc`). The live root
`.github/workflows/mirror.yml` uses the standards reusable workflow and
has no pipe-to-shell.
- The README notes the removal, and the dead baseline acknowledgement
under the template's old path (from before #417) is retired.
- **Qualified five cross-repo paths**, which removes the SD022 findings:
`echidnabot/src/api/`, `echidnabot/src/scheduler/` and
`echidnabot/src/modes/` in `issues/echidnabot-01-…md` and
`.github/issues/echidnabot-01-…md`, and `echidnabot/src/dispatcher/` in
`docs/handover/PARADISEO-ROADMAP-PROMPT.adoc`.
- SD022 flags only a *root-relative* `src/<dir>/`; per its lookbehind in
`hypatia/lib/rules/structural_drift.ex`, a prefixed `src/` "belongs to
that other tree/crate/repo".
- These paths are echidnabot's, so the qualified form is also the
accurate one.
- My first push baselined them instead. The **Exemption ratchet**
correctly rejected that (71 → 73: "remove the finding rather than the
report"), so `0850e4a` replaces it.
- **`.hypatia-baseline.json` → JCS** (RFC 8785) I-JSON with a final LF,
which `.editorconfig` requires. It is one line with sorted keys, a fixed
point of the canonicaliser. It now has **70 entries, below `main`'s
71**.

## RSR Quality Checklist

### Required

- [x] Tests pass (no code change)
- [x] Code is formatted (baseline is canonical JCS)
- [x] Linter is clean
- [x] No banned language patterns
- [x] No `unsafe` blocks
- [x] No banned functions
- [x] SPDX license headers present on all new/modified source files
- [x] No secrets, credentials, or `.env` files included

### As Applicable

- [x] Documentation updated (`ci-templates/README.adoc`, cross-repo
paths)
- [ ] Others: n/a

## Testing

```
standards scripts/check-exemption-ratchet.sh 2dbf3c4   (what CI runs)
  96e919c (baseline approach): GREW 71 -> 73, FAILED      ← reproduces the CI failure
  0850e4a (this head):         SHRANK 71 -> 70, OK
standards@571cc734 scripts/apply-baseline.sh             (the pinned reusable's filter)
  new baseline: schema check passes (exit 0)
SD022 regex (?<[\w./-])src/([A-Za-z0-9_][A-Za-z0-9_-]*)/ over the three docs:
  every remaining root-relative src/<dir>/ is a real echidna directory (rust, abi, zig_ffi, chapel)
```

## Stack

1. #432: `quinn-proto` lockfile bump
2. **This PR**: Hypatia findings fixed at source, baseline → JCS
3. ECH-05 follow-ups and format norms (next)

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

https://claude.ai/code/session_019a95kk88TZ1iegsBK3kox3

---------

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

Author: hyperpolymath

.github/issues/echidnabot-01-adaptive-ci-portfolio-scheduler.md

@@ -21,7 +21,7 @@ Applying Automated Algorithm Selection and Parameter Tuning principles from Para
 ## Current State
 
 Verified against echidnabot@ae5283323b815f82d2a556080b59e0bb648de62b:
-- `enqueue_repo_jobs` in `src/api/webhooks.rs` creates one job per enabled prover (VERIFIED: iterates over `repo.enabled_provers`)
+- `enqueue_repo_jobs` in `echidnabot/src/api/webhooks.rs` creates one job per enabled prover (VERIFIED: iterates over `repo.enabled_provers`)
 - `JobLimiter` defaults to 10 global / 3 per repo concurrent jobs (VERIFIED: in limiter.rs)
 - Static 300 second timeouts are used as default (VERIFIED: `default_timeout()` returns 300 in config.rs)
 - `manifest [provers.<slug>] timeout_seconds` is wired into dispatch (VERIFIED: accessed in manifest.rs, used in echidna_client.rs)