Marketplace AL Language extension cannot publish to BC 29 sandbox: server requires Debugger 9.0, latest release/pre-release support only up to 8.0 #8356

Summary
After our BC SaaS sandbox was updated to BC 29, the AL Language extension from
the VS Code Marketplace can no longer connect to it. Download Symbols, Publish
(Ctrl+F5) and Debug (F5) all fail immediately with:

Error: This AL extension version for Visual Studio Code cannot be used with
the specified server. Please update the AL extension from the Visual Studio
Code marketplace.

There is no newer version on the Marketplace to update to.

Environment

• Business Central: IN Business Central 29.0 (Platform 29.0.55857.0 + Application 29.0.54011.55935)
• Environment type: SaaS Sandbox
• Server reports: Runtime 18.0, Web API 7.0, Debugger 9.0
• VS Code 1.141.0, Windows 11 (10.0.26200)
• app.json: "application": "29.0.0.0", "runtime": "18.0"

Results per AL extension version

Steps to reproduce

1. Install the latest AL Language extension from the Marketplace
   (18.0.2819426, or pre-release 30.0.2813176).
2. Open a project targeting application 29.0.0.0 / runtime 18.0.
3. Run AL: Download Symbols, Ctrl+F5 or F5 against the BC 29 sandbox.
4. The request to /v2.0//dev/metadata?tenant= returns
   the version-incompatibility error. Supported runtimes and Web API match the
   server, but debugger 9.0 is missing from "Supported debuggers".

Observations

• Runtime (18.0) and Web API (7.0) are supported by all versions tested; only
  the debugger version (9.0) blocks the connection.
• The AL VSIX shipped in the sandbox's own artifact (29.0.54011.55935) supports
  only debuggers up to 7.0, so the server's debugger endpoint appears to have
  been updated ahead of the AL tooling released with that build.
• The only working build we found, 18.1.2842859, is not available on the
  Marketplace. We had to extract it manually from the BC artifact CDN.

Workaround in use
Manually installed ALLanguage.vsix 18.1.2842859 extracted from
https://bcartifacts-exdbf9fwegejdqak.b02.azurefd.net/sandbox/29.0.54011.56119/platform
(path inside: ModernDev/PFiles/Microsoft Dynamics NAV/290/AL Development Environment/ALLanguage.vsix).
Auto-update for the AL extension has to be disabled, otherwise VS Code
replaces it with the incompatible Marketplace build.

Expected
A Marketplace release (or pre-release) of the AL Language extension that
supports debugger protocol 9.0 should be available when sandboxes are
updated to it.

Request
Please publish an AL Language extension version supporting debugger 9.0 to
the Marketplace, or confirm the recommended version for BC 29 Platform 29.0.55857.0.

launch.json
publish-error-output.txt