changelog: Cutover to remove NEXT_CHANGELOG.md

[janniklasrose]

Changes

• Remove NEXT_CHANGELOG.md — the .nextchanges/ system fully drives the release now, so nothing reads it anymore.
• Migrate its two pending v1.7.0 entries to .nextchanges/ fragments (verified they render identically).
• Update the remaining NEXT_CHANGELOG references in the onboard-team-area skill to .nextchanges/.

Why

Follow-up cutover to #5534. That PR left NEXT_CHANGELOG.md in the tree (unused) to stay focused; release_tagging.py already renders CHANGELOG.md straight from .nextchanges/ fragments. This deletes the now-vestigial file and its last references.

Tests

• task check-changelog passes (fragments + version valid).
• Confirmed release_tagging.py reads only .nextchanges/ (fragments + version), never NEXT_CHANGELOG.md, so the deletion changes no release behavior.
• Rendering the two migrated fragments reproduces the original NEXT_CHANGELOG.md body byte-for-byte.

Stacking

Stacked on top of #5534 (janniklasrose/changelog-merge-conflicts). Merge that first; this PR's base should be retargeted to main once #5534 lands.

This pull request was written by Isaac, an AI coding agent.

[eng-dev-ecosystem-bot]

Integration test report

Commit: ea67c50

Run: 29110073752

	Env	🟨​KNOWN	💚​RECOVERED	🙈​SKIP	✅​pass	🙈​skip	Time
💚​	aws linux		4	4	230	1078	5:06
💚​	aws windows		4	4	232	1076	7:02
💚​	aws-ucws linux		4	4	316	995	5:55
💚​	aws-ucws windows		4	4	318	993	7:43
💚​	azure linux		4	4	230	1077	5:14
💚​	azure windows		4	4	232	1075	7:14
💚​	azure-ucws linux		4	4	318	992	6:32
💚​	azure-ucws windows		4	4	320	990	7:28
🟨​	gcp linux	3	1	4	229	1079	7:40
💚​	gcp windows		4	4	231	1077	6:57

8 interesting tests: 4 SKIP, 3 KNOWN, 1 RECOVERED

	Test Name	aws linux	aws windows	aws-ucws linux	aws-ucws windows	azure linux	azure windows	azure-ucws linux	azure-ucws windows	gcp linux	gcp windows
💚​	TestAccept	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R
🙈​	TestAccept/bundle/invariant/no_drift	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/bundle/resources/vector_search_endpoints/drift/recreated_same_name	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/bundle/resources/vector_search_indexes/recreate/embedding_dimension	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/ssh/connection	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🟨​	TestFetchRepositoryInfoAPI_FromRepo	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	🟨​K	💚​R
🟨​	TestFetchRepositoryInfoAPI_FromRepo/root	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	🟨​K	💚​R
🟨​	TestFetchRepositoryInfoAPI_FromRepo/subdir	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R	🟨​K	💚​R

Top 10 slowest tests (at least 2 minutes):

duration	env	testname
6:11	aws windows	TestAccept
6:09	azure-ucws windows	TestAccept
6:07	aws-ucws windows	TestAccept
6:06	gcp windows	TestAccept
6:03	azure windows	TestAccept
2:59	azure linux	TestAccept
2:55	gcp linux	TestAccept
2:53	azure-ucws linux	TestAccept
2:53	aws linux	TestAccept
2:46	aws-ucws linux	TestAccept

[janniklasrose]

note https://github.com/databricks/cli/blob/main/.nextchanges/version is already at 1.8.0 so no need for cutover

[github-actions]

Approval status: pending

/acceptance/bundle/ - needs approval

Files: acceptance/bundle/resource_deps/volume_path_job_ref/test.toml
Suggested: @denik
Also eligible: @pietern, @anton-107, @andrewnester, @shreyas-goenka, @lennartkats-db

General files (require maintainer)

Files: .nextchanges/cli/5888-ssh-connect-env-interpreter.md, NEXT_CHANGELOG.md
Based on git history:

• @denik -- recent work in ./

_{Any maintainer (@andrewnester, @anton-107, @denik, @pietern, @shreyas-goenka, @simonfaltum, @renaudhartert-db) can approve all areas.
See OWNERS for ownership rules.}