feat(cnpg): Add PostgreSQL 17 and 18 support

[nblondiau]

Description

Adds PostgreSQL 17 and 18 support to the CNPG integration of the common library. Users can now set pgVersion: 17 or pgVersion: 18 on a CNPG cluster and the correct operand image is selected automatically.

This extends both validation layers - the runtime _validation.tpl guard and the pgVersion JSON-schema enum in schemas/cnpg/cnpg.json (with the generated docs/cnpg/index.md updated to match) - so the new versions are accepted by downstream consumers, not just the template.

Fixes #

Type of change

• Feature/App addition
• Bugfix
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor of current code
• Documentation Changes

How Has This Been Tested?

• Unit tests: added 7 cases to cluster_spec_test.yaml asserting the correct spec.imageName for each new image key (postgres 17/18, postgis 17/18, vectors 17, vectorchord 17/18), plus a negative case in cluster_validation_test.yaml proving type: vectors + pgVersion: 18 fails with a clear message (pgvecto.rs has no PG18 build). Full common-test suite passes locally (helm unittest -f "tests/**/*.yaml").
• Install tests: added cnpg-pg17-values.yaml, cnpg-pg18-values.yaml and cnpg-pg18-postgis-values.yaml to the common-tests install matrix; these deploy real CNPG clusters (operator chart 0.27.1) on PG17, PG18 and PG18+PostGIS via ct install.
• Every image tag and digest was verified against the live ghcr.io registry before pinning.

Notes:

New images and pinned digests:

Key	Repository	Tag
postgres17Image	ghcr.io/cloudnative-pg/postgresql	17.10
postgres18Image	ghcr.io/cloudnative-pg/postgresql	18.4
postgresPostgis17Image	ghcr.io/cloudnative-pg/postgis	17-3.5
postgresPostgis18Image	ghcr.io/cloudnative-pg/postgis	18-3.6-standard-bookworm
postgresVectors17Image	ghcr.io/tensorchord/cloudnative-pgvecto.rs	17.5-v0.4.0
postgresVectorchord17Image	ghcr.io/tensorchord/cloudnative-vectorchord	17.9-1.1.1
postgresVectorchord18Image	ghcr.io/tensorchord/cloudnative-vectorchord	18.3-1.1.1

• PostGIS 18: published only under the new tag scheme (18-3.6-standard-bookworm); no plain 18-3.x tag exists in ghcr.io/cloudnative-pg/postgis, so that scheme is used for the 18 entry while 15-17 keep their existing plain tags.
• pgvecto.rs 18: ghcr.io/tensorchord/cloudnative-pgvecto.rs has no PostgreSQL 18 build (the project is superseded by VectorChord - its highest major is 17), so postgresVectors18Image is intentionally not added. VectorChord covers PG18.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made changes to the documentation
• I have added tests to this description that prove my fix is effective or that my feature works
• I increased versions for any altered app according to semantic versioning
• I made sure the title starts with feat(chart-name):, fix(chart-name):, chore(chart-name):, docs(chart-name): or fix(docs):

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[CLAassistant]

All committers have signed the CLA.

[alfi0812]

Needs to be retargeted towards common2026 branch.
Also need to keep our default template for prs.
Missing all testing of the new images like we have for previous versions. (Possivly unit-tests + install tests)

[alfi0812]

See comment above

[alfi0812]

There also is a postgis 18 image. So let's use proper research and more human work then Ai dumbs please. Thanks

[alfi0812]

PostGIS and pgvecto.rs images for PG 18 are not yet available from upstream

Wrong

[alfi0812]

All existing tests pass (1352/1352)

That just covers or unit tests not install tests and also misses any additional tests for your changes.

[alfi0812]

cluster_validation_test.yaml: Updated test to expect new valid versions

Doesn't seem to be part of this pr. So wrong claim. Missing any testing

[alfi0812]

Got some work to do to make that work again. (Proper rebase)

[nblondiau]

Thank you for your time.
Let's hope I haven't bitten off more than I can chew...

Now for Puffin

[alfi0812]

@Crow-Control should be in a state worth for you looking at it