build: centralize maven repo declarations

[dsmiley]

Centralize repository declarations (single mirror choke-point)

Motivation

Repository declarations (mavenCentral(), gradlePluginPortal()) were scattered
across the build in every distinct Gradle repository scope: plugin resolution,
project dependencies, the buildscript classpath of several convention scripts, and
the two included builds. There was no single place for an enterprise to redirect
resolution to an internal mirror (Artifactory/Nexus).

What this does

Introduces one shared file, build-tools/build-infra/declare-repositories.gradle,
as the single source of repository declarations, and applies it into every
consumption scope via apply from: ..., to: <handler>:

• settings.gradle -> pluginManagement (plugin resolution)
• gradle/globals.gradle -> allprojects (project dependencies)
• solr/ui/build.gradle.kts (keeps its module-specific google(), routes the rest)
• the buildscript {} blocks in git-status, rat-sources, jar-checks,
  randomization, markdown, and solr/docker (buildscript classpath)
• build-tools/build-infra and build-tools/missing-doclet (included builds)

Placing the file under build-tools/build-infra/ lets the classloader-isolated
included builds reach it by relative path. This follows the same pattern Lucene
uses upstream.

Enterprise mirror

Set one of the following and the entire build (including the included builds, which
inherit JVM system properties / environment) resolves exclusively from the mirror,
excluding public repositories:

• -Dsolr.maven.repo.url=https://.../maven (or systemProp.solr.maven.repo.url=...
  in gradle.properties)
• SOLR_MAVEN_REPO_URL=https://.../maven environment variable

With neither set, behavior is unchanged (mavenCentral() + gradlePluginPortal()).

Notes

• Removed a dead commented-out LucenePrerelease repository template in
  gradle/globals.gradle (still in git history); it didn't belong in a file shared
  with pluginManagement.
• Intentionally left alone: publishing targets in gradle/maven/*.gradle and the
  dev-only mavenLocal() in gradle/lucene-dev/* (not consumption repos).

Verification

• gradlew help (all scopes), :build-infra:help, and :solr:ui:help
  (-PdisableUiModule=false) all configure cleanly.
• Setting a bogus mirror via both the system property and the env var redirects all
  scopes to it exclusively (plugin resolution fails against the bogus URL only),
  confirming the override works and public repos are dropped.
• Dependency locking still validates for both the buildscript classpath and project
  configurations; no lockfiles changed (mavenCentral remains first, so resolution is
  unchanged when no mirror is set).

🤖 Generated with Claude Code

[kotman12]

Does enterpriseMirror mean something or does it just need a string? If the latter then IMO "enterprise" has a certain commerce/profit-making connotation which is probably correct in most cases but in the off chance it is not (non-profit/government) maybe we dont have to be so opinionated on this being an "enterprise" mirror. But enterprise is an overloaded term in java so thats a really small nit.

[dsmiley]

It's any name. I'll see if I can remove it. I think of "enterprise" as your business, no matter it's nature.

[dsmiley]

it can be removed but seems a best practice / helpful. I'll leave it commented and put "yourEnterpriseMirror"

[dsmiley]

Will merge this tomorrow.

[dsmiley]

I validated this at work -- a build that occurred in a docker container. Disclaimer: did so with several modules disabled like the UI and jsClient. Thus I didn't need NodeJS. Some more adjustments might be needed to accommodate that.