perf(webapp): drop archived branch environments from project env loads (#4595)

## What

Several project pages loaded **every** `RuntimeEnvironment` row for a
project, including the archived preview-branch environments that are
never shown in the UI. On a project with heavy preview-branch usage that
means thousands of rows per load, producing a large result set and a
rare multi-second tail on the environment lookup (~30s outlier observed
via Insights on `RuntimeEnvironment` projectId lookups, fingerprint
`f2b3ecab…`).

The tail is dominated by the size of the result being
parsed/transferred, not by the query plan (it already used
`RuntimeEnvironment_projectId_idx` with no over-read). So the fix is to
stop returning archived branch environments.

## Diagnosis correction

The ticket framed this as a "large `projectId IN` list" and suggested
bounding the IN list / cursor pagination. It's actually a Prisma
**nested relation load** on a *single-project* `project.findFirst`, so
the `IN (...)` holds one projectId and the trailing `OFFSET $1` is
Prisma's relation-subquery artifact. The 4,644 rows in the observed
execution were **one project with ~4,644 environments** (accumulated
archived branches), not many projects.

## Change

Filter the `environments` relation load to `archivedAt: null` (base envs
never archive, so only archived preview branches are excluded):

- `ProjectPresenter.server.ts`
-
`orgs.$organizationSlug.projects.$projectParam.{concurrency,apikeys,environment-variables,settings}.ts`
(best-env resolvers)

And remove an **unused** `environments` select from
`DeploymentListPresenter.server.ts` (it was selected but never read).

`loadProjectEnvironments` (replay route) already filters `archivedAt:
null` + env type; this change follows that existing precedent.

## Evidence (isolated stack, seeded one project with 2,000 archived
branch envs + 4 active)

`EXPLAIN (ANALYZE)` of the exact presenter sub-select:

| | rows returned | index |
|---|---|---|
| before (unfiltered) | **2004** | `RuntimeEnvironment_projectId_idx` |
| after (`archivedAt IS NULL`) | **4** (`Rows Removed by Filter: 2000`)
| same index, no plan change |

500x fewer rows to the client, which is what removes the parse-on-load
tail. No new index needed. `typecheck --filter webapp` clean. UI
verified: project layout, Deploys page, and the concurrency best-env
redirect all render with the 2,000 archived branches present in the DB
and zero console errors.

## Rollout / rollback

Straight deploy, no migration. Rollback is revert-only (read-path
filter, no data change). Old and in-flight rows read correctly under
both the old and new code.

## Limitation

A project with thousands of *active* branches would still load them all;
in practice active branches are few (branches are archived when their
work merges). Hard-bounding active branches would be a larger change and
is out of scope here.

.server-changes/bound-project-environment-loads.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+Project pages now load faster for projects with a large number of preview branches, by no longer loading archived branch environments that aren't shown.