CP-13653 linux-pkg: disable windows-connector's post-push auto-trigger, require manual trigger to publish

[vimleshmishra]

Problem

windows-connector's post-push Jenkins job auto-triggers on every push to dlpx-app-gate, even though connector source changes are infrequent and dlpx-app-gate sees heavy, unrelated traffic. Most of these builds are pure rebuild churn with no actual connector source change, and any real build-health regression is indistinguishable from that noise without added machinery to tell the two apart.

Solution

Disable the auto-trigger and require a human to manually trigger a build/publish instead:

• Set DEFAULT_PACKAGE_GIT_URL="none" in packages/windows-connector/config.sh. The shared Job DSL (devops-gate/jenkins/jobs/linux_pkg_build_package.groovy) already disables a job's push trigger when its git URL is falsy/"none" — no devops-gate change is needed for this.
• Since PACKAGE_GIT_URL would otherwise also resolve to "none" (breaking source fetch), override the fetch() hook in the same config.sh to hardcode the real dlpx-app-gate URL directly, bypassing that variable.
• Add packages/windows-connector/README.md documenting the new process end-to-end: why the trigger was removed, how the mechanism works, how to bump connectorDebVersion, how to test via git-ab-pre-push -b windows-connector before merging, and how to publish a new latest after merging.

This supersedes the earlier automated skip-detection design (connectorDebVersion cache-check + NOT_BUILT signaling), tracked in #407 and devops-gate#4772 — both are being closed/discarded in favor of this simpler approach.

Testing Done

Verified end-to-end on a personal Jenkins developer controller (jenkins-vmishra.dcol2.delphix.com, via JenkinsManager configure -j ops -g linux-pkg pointed at this branch on my fork):

• Trigger suppression: the regenerated windows-connector/post-push job has no SCM/push-trigger property, and its auto-generated description reads "Triggers are disabled for this job, so it must be run manually."
• Source fetch still works: manually triggered post-push build Initial review #1 — it cloned the real dlpx-app-gate source via the fetch() override, BUILD SUCCESSFUL (Gradle), and the job finished SUCCESS end-to-end.
• Publish path confirmed isolated: published to s3://snapshot-de-images/builds/jenkins-ops.vmishra/.../post-push/latest — the personal-controller-specific jenkins-ops.<user> S3 prefix, not real production latest.

Notes to Reviewers

Tracked under CP-13653, epic CP-13579.

A companion pointer comment was added in dlpx-app-gate's appliance/host/windows/build.gradle, next to connectorDebVersion, linking back to this package's README — since that's the actual entry point most people will hit when making a connector change.