docs: enable PPL Query Builder by default, remove enablement docs

[joshuali925-osdbot]

Description

Follow-up to #383. Enables the PPL Query Builder feature flag by default across the observability stack setup and removes the now-unnecessary enablement instructions from the docs.

Enable the flag by default — added explore.logsQueryBuilder.enabled: true to:

• docker-compose/opensearch-dashboards/opensearch_dashboards.template.yml
• charts/observability-stack/values.yaml
• charts/observability-stack/values-anonymous-auth.yaml

These configs already set explore.enabled: true, so the builder is now on out of the box.

Docs cleanup — since the builder ships enabled by default in this stack:

• Removed the ## Enabling the builder section from ppl/query-builder.md
• Removed the :::note[Availability] block that told users to flip the flag (and its now-dangling #enabling-the-builder anchor link)
• Dropped the "and how to enable it" reference and reworded the conditional "With the PPL Query Builder enabled" phrasing on investigate/discover-logs.md

Testing

• Ran the Starlight docs build (npm run build). The link validator reports the same 41 pre-existing invalid links (16 files) on both main and this branch — this change introduces no new broken links, and specifically leaves no dangling #enabling-the-builder anchor.
• Validated YAML syntax of all three modified config files.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.62%. Comparing base (b93a0b7) to head (8ecf8e9).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #387   +/-   ##
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  Coverage   55.62%   55.62%           
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  Files           4        4           
  Lines         169      169           
  Branches       47       47           
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  Hits           94       94           
  Misses         74       74           
  Partials        1        1           

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[joshuali925]

this needs 3.8 or nightly before it would work

[joshuali925-osdbot]

Looking into the CI failures now. Both e2e-compose and e2e-install fail because opensearch-dashboards never becomes healthy. I reproduced it locally: OSD 3.7.0 (the version this stack pins) rejects explore.logsQueryBuilder.enabled with a fatal ValidationError: [config validation of [explore].logsQueryBuilder]: definition for this key is missing and refuses to boot. That flag only ships in OSD 3.8.0 (as the docs this PR removed correctly stated). Working on a fix.

[joshuali925-osdbot]

Fixed — reverted the premature enablement (82a4819)

Root cause

Both e2e-compose and e2e-install failed because opensearch-dashboards never became healthy. I reproduced it locally against opensearchproject/opensearch-dashboards:3.7.0 (the version pinned in .env and the Helm values):

FATAL  ValidationError: [config validation of [explore].logsQueryBuilder]: definition for this key is missing

OSD validates config keys at boot and aborts on any unknown key. explore.logsQueryBuilder does not exist in OSD 3.7.0 — it ships in OSD 3.8.0, exactly as the :::note[Availability] block this PR removed stated. So enabling the flag by default made OSD crash-loop on a stack that runs 3.7.0.

Fix

Reverted commit 8ecf8e9. This removes explore.logsQueryBuilder.enabled: true from the three config files and restores the accurate "Enabling the builder" docs. The branch tree is now identical to main.

Verified locally:

• OSD 3.7.0 boots cleanly with the reverted config (no ValidationError).
• YAML of all three config files is valid.
• Docs/config now match the known-good main state (net-zero diff), so the restored #enabling-the-builder anchor resolves.

Note on this PR

Because the revert restores the branch to main, this PR now has an empty diff. Enabling the PPL Query Builder by default is blocked on the stack upgrading to OSD 3.8.0 (bumping OPENSEARCH_VERSION / OPENSEARCH_DASHBOARDS_VERSION in .env and the Helm image tags, which also requires bumping the OpenSearch server to 3.8.0 for version parity). That is a broader change and a maintainer version-policy decision, so I did not fold it into this CI fix.

Recommendation: close this PR and revisit once the stack moves to OSD 3.8.0, or convert it into a coordinated 3.7.0 → 3.8.0 version bump if that upgrade is desired now.

[joshuali925-osdbot]

✅ CI is now green on 82a4819 — both e2e-compose and e2e-install pass with the revert.

Note this leaves the PR with an empty diff (branch is identical to main). As flagged earlier, enabling the PPL Query Builder by default is blocked on upgrading the stack to OSD 3.8.0 (the explore.logsQueryBuilder config key doesn't exist in the pinned 3.7.0, which is what crash-looped CI).

Recommend either closing this PR and revisiting after the 3.8.0 upgrade, or repurposing it into a coordinated OpenSearch + OSD 3.8.0 version bump if that upgrade is wanted now. Deferring to maintainers on that call.