chore: remove java-area120-tables library - #14758

…4942)

feat(shopping-merchant)!: remove discontinued Merchant API v1beta

## Description

Merchant API v1beta (`google/shopping/merchant/*/v1beta`) is
discontinued. Since 2026-06-01 the server rejects every v1beta call. The
v1beta protos will be removed from googleapis once every language stops
generating them. This PR stops generating v1beta in google-cloud-java
and removes the v1beta artifacts that are left behind, in the 13
Merchant libraries that ship both v1 and v1beta:

shopping-merchant-{accounts, conversions, datasources, inventories,
issue-resolution, lfp, notifications, order-tracking, products,
promotions, quota, reports, reviews}

v1 stays in every library, and so does reports v1alpha. The libraries
and their per-library BOMs (`google-shopping-merchant-<api>-bom`) are
kept.

## Changes

- `librarian.yaml`: removed the `google/shopping/merchant/<api>/v1beta`
entry from `apis:` in each of the 13 libraries. We remove the path
instead of using `skip_generate`, so v1 keeps being generated.
- Removed by `librarian generate`:
- the v1beta GAPIC client sources
(`com.google.shopping.merchant.<api>.v1beta`), with their tests and
stubs;
  - the v1beta generated samples;
  - the v1beta GraalVM `reflect-config.json`.
- Removed the `proto-google-shopping-merchant-<api>-v1beta` and
`grpc-google-shopping-merchant-<api>-v1beta` modules (26 modules).
- Library parent `pom.xml`: removed the v1beta `<module>` and
`dependencyManagement` entries.
- `google-shopping-merchant-<api>-bom/pom.xml`: removed the v1beta
proto/grpc entries.
- `google-shopping-merchant-<api>/pom.xml`: removed the v1beta proto
dependency and the test-scope grpc dependency.
- Removed the leftover `v1beta/stub/Version.java` from each client
module.
- `versions.txt`: removed the 26
`proto-/grpc-google-shopping-merchant-<api>-v1beta` entries. This
follows #14540 and #14758.
- Library `README.md`: the version snippet as regenerated by librarian.

Nothing outside the 13 library directories needed a change:
- the root `README.md` lists libraries, not versions;
- `gapic-libraries-bom` and `java-cloud-bom` (libraries-bom,
google-cloud-bom, libraries-release-data, dependency-convergence tests)
have no Merchant entries;
- CHANGELOG history is kept.

## Breaking change

This is a **breaking removal**:
- the
`com.google.shopping.api.grpc:proto-google-shopping-merchant-*-v1beta`
and `grpc-google-shopping-merchant-*-v1beta` artifacts are no longer
published;
- the `com.google.shopping.merchant.*.v1beta` classes are removed from
`com.google.shopping:google-shopping-merchant-*`.

The API is discontinued and every v1beta call has failed since
2026-06-01, so no working code depends on these. Users should move to
`v1`. Already published versions stay on Maven Central.

`release-please-config.json` uses `"versioning": "always-bump-minor"`,
so this ships as a **minor** release with a ⚠ BREAKING CHANGES section
in the CHANGELOG, as #14540 did in 1.93.0.

## Verification

- `librarian generate` (Librarian v0.51.0) ran for all 13 libraries,
then `librarian tidy`.
- Running `librarian tidy` again produces no diff. Running `librarian
generate` again (reports, products) produces no diff and doesn't
re-create any v1beta module.
- `mvn install -DskipTests -pl <13 client modules> -am`, run from the
repo root with JDK 17, gives BUILD SUCCESS. reports builds v1 and
v1alpha.
- `git grep` for `merchant-.*-v1beta`, `merchant/<api>/v1beta` and
`merchant.<api>.v1beta` finds no hits outside CHANGELOG history. The
remaining `v1beta` text is upstream v1 proto doc comments in products v1
("Note: For calls to the v1beta version…"). That comes from googleapis
and isn't changed here.

Internal tracking: b/581492005 (parent b/580887933)

The 13 library README.md files also update the Maven/Gradle/SBT version
snippets from 1.29.0 to 1.30.0; this comes from regeneration catching up
with main and is unrelated to v1beta.

🤖 _Opened by an AI agent on behalf of zhumin._