improve avm module completion readability with suffix labels and prefix descriptions

[polatengin]

Fixes #18957

Description

Improve module completion readability by adding tooltip with detailed information about the selected AVM module.

Changes I made;

• Added AVM display name cache preload from AVM CSV indexes (utility, pattern, resource) at language server startup.
• Updated module completion resolve to use ModuleDisplayName as tooltip title for AVM modules.
• Added lightweight trace-gated preload logs (success counts and failure fallback).
• Wired new services through DI and startup warmup.
• Updated unit and integration tests to validate tooltip shape and AVM title behavior.

Checklist

• I have read and adhere to the contribution guide.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 22597043377)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 22597043377

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 22597043377"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 22597043377

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 22597043377"

[matebarabas]

Hi @polatengin, thanks for this PR! Let's align on this internally first before proceeding. Thanks again!