support metadata service

[valner]

No description provided.

[Copilot]

Pull request overview

This PR adds support for retrieving metadata from an Instance Metadata Service (IMDS) with fallback mechanisms. The implementation replaces direct cloud-init command execution with HTTP-based metadata service calls, includes caching with TTL, and maintains backward compatibility with file-based metadata retrieval.

Changes:

• Replaced cloud-init command execution with HTTP-based IMDS requests for fetching instance metadata
• Added caching mechanism with 5-minute TTL for instance data to reduce redundant network calls
• Implemented fallback logic: IMDS primary → IMDS fallback URL → local files

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
internal/metadata/metadata.go	Core implementation of IMDS client with caching, fallback URLs, and file-based fallback
internal/metadata/metadata_test.go	Comprehensive test suite covering IMDS requests, caching, TTL expiration, and fallback scenarios
internal/config/config.go	Updated default configuration with IMDS URLs and token type
internal/client/client.go	Renamed variable from cloudInitFallback to instanceIdFallback to reflect new implementation
internal/client/client_test.go	Updated mock calls to match new GetInstanceId signature with three return values
debian/usr/sbin/nebius-observability-agent-updater-run.sh	Modified to fetch updater endpoint override from IMDS instead of local file

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