[Generated by SRE Agent] release: bump VERSION to 3.9.0 and add release notes

[azure-monitor-assistant]

Bumps the Container Insights (ama-logs) agent version to 3.9.0 and adds release notes.

Changes

• VERSION: 3.8.0 -> 3.9.0
• ReleaseNotes.md: new 3.9.0 entry covering all PRs merged into ci_prod since the 3.8.0 build (fd42f68, fix: restore Linux Go plugin telemetry and outbound TLS (godebug tlsmlkem=0) #1778).
  • Common: [Generated by SRE Agent] fix: remove inline comment corrupting Ignore_Older and improve networkflow error logging #1793, Fix Telegraf options removed in 1.40 on Linux and Windows (fieldpass -> fieldinclude, pid_tag -> tag_with) #1764, Prevent shell injection in ConfigMap-derived environment settings #1790, fix(windows): start telegraf on Windows Server 2025 hosts #1782, Upgrade telegraf-agent to 1.40.1 #1789, Upgrade Windows Telegraf to 1.40.0 #1785
  • Infra: Update backdoor-deployment skill to use the in-repo chart #1795, [tests] validate agent version telemetry & heartbeat #1786, fix(test): allow all-nodes log generator on Windows 2025 #1791, Add rollbackVersion option and default releaseTrain to stable in Ev2 SDP pipelines #1781, [Generated by SRE Agent] ci: emit Azure Linux base image version in build summary #1780, [Generated by SRE Agent] docs: update release notes for 3.7.0 and 3.8.0 #1779
  • Dependency changes: Telegraf 1.39.3 -> 1.40.1 (Linux), 1.24.2 -> 1.40.1 (Windows). Go 1.27.0, MDSD 1.42.0, Fluent-bit, Fluentd, Ruby, Windows AMA unchanged.

Follow-up

The image tag (3.9.0-<tbd>) and Azure Linux version (<tbd>) are placeholders. A follow-up PR will fill them in after the ci_prod build (pipeline 444) for this merge completes.

Template: #1775 (3.7.0 release).

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Created by Azure SRE Agent: Open thread

[azure-monitor-assistant]

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[suyadav1]

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