fix(dev): run the local e2e tier against the app CI runs

Two specs failed locally and passed in CI, which is the least useful
direction for a disagreement to point.

**`dev-headless.sh` was the only launcher not stubbing out the
catalog.** `seed-sandbox.sh` and `ci.yml` both send
`YJ_CORE_INDEX_URL` to a dead address; the dev launcher did not, so the
app downloaded and built the real ~1M-row Explore catalog into the
run's YJ_HOME and every local `make e2e` after that ran against a world
CI never sees. Found by reading the failure screenshot: the spec had
searched Explore for its fixture album and the page was full of real
ones. It defaults to the dead address now and takes an explicit one for
exploring by hand.

**And the shared backend carries spec state between runs.**
`explore-shelves` staged its catalog only `IfEmpty`, so one album row
left behind by `requested-badge` satisfied that gate: the shelves were
drawn from a single foreign row and the artist card the spec clicks did
not exist. It failed on the *second* local run and passed on the first,
and never in CI, where every run gets a fresh home.

"Is the catalog empty" was the wrong question and "are my rows there"
is the right one, so staging is unconditional (INSERT OR IGNORE keyed
on the MBID) and the assertion moved from *this insert wrote a row* to
*every fixture row is present*. That is both idempotent and stronger:
an MBID that fails CHECK(length(mbid) = 16) is silently dropped by OR
IGNORE, which the old per-insert count caught only on a cold catalog
and the new one catches always.

Verified by running the whole suite twice against one app: 97/3 before,
100 passed both times after.

.pi/skills/yellowjacket-dev/SKILL.md

@@ -96,6 +96,15 @@ reference, because you need them *before* the failure, not after.
   Run against the `bulk` seed a measurement session left behind and a
   third of them fail (13 of 36, when it was measured), in a list that
   reads exactly like a regression in whatever you are holding. `make dev-headless SEED=default` first.
+- **The catalog is stubbed out locally now, like CI.**
+  `dev-headless.sh` defaults `YJ_CORE_INDEX_URL` to a dead address
+  because it was the only launcher that did not — `seed-sandbox.sh` and
+  `ci.yml` always have. Without it the app downloads the real ~1M-row
+  Explore catalog into the run's `YJ_HOME`, and specs that stage their
+  own catalog rows then search a million real ones and fail *locally
+  only*, which reads as a regression and is an environment. Pass
+  `YJ_CORE_INDEX_URL=<real url>` when you want the real catalog to
+  explore by hand.
 - **…and the suite spends state it cannot always give back.**
   `view-lifecycle.spec.ts` **skips an autotag album** on every run, out
   of the eleven the seed has, and does not put it back — so around the