[management] refactor: introduce incremental network map builder

[crn4]

Describe your changes

This PR refactors the network map generation approach by introducing a new, experimental network map builder. Instead of rebuilding the map from scratch, this builder applies incremental updates based on network map change events.

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Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)

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Documentation

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• I added/updated documentation for this change
• Documentation is not needed for this change (explain why)

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Paste the PR link from https://github.com/netbirdio/docs here:

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[Copilot]

Pull Request Overview

This PR introduces an experimental incremental network map builder to optimize network map generation performance. Instead of rebuilding maps from scratch each time, the new builder applies incremental updates based on network map change events.

• Introduces the new NetworkMapBuilder with incremental update capabilities
• Adds environment variable NB_EXPERIMENT_NETWORK_MAP to enable the experimental builder
• Implements incremental peer add/delete operations and cache management

Reviewed Changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
management/server/types/networkmapbuilder.go	Core implementation of the incremental network map builder with caching
management/server/types/networkmap_golden_test.go	Comprehensive test suite with golden file testing for both old and new builders
management/server/types/networkmap.go	Moved network map logic from account.go with experimental builder integration
management/server/user.go	Added network map cache updates for peer expiration
management/server/peer.go	Integrated experimental builder calls for peer operations
management/server/account.go	Added experimental builder flag and holder for cache management
Multiple manager files	Added network map cache recalculation calls for various operations

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[Copilot]

The comment suggests confusion about the logic. Clarify why peer.Key is stored in r.Peer field and reference the specific comment mentioned.

Suggested change

	// maybe here is some mess - here we store peer key (see comment below)
	// Here we store peer.Key in r.Peer for enabled routes.
	// This is intentional and follows the logic from the original account.getRoutingPeerRoutes (see comment at line 635 below),
	// where for group routes we store peerID, but for enabled routes we store the peer's key.

[Copilot]

The inconsistency between storing peer.Key in some places and peerID in others (as noted in the comments) suggests potential confusion. Consider using consistent field naming or add clear documentation about when each is used.

Suggested change

	// and here we store peer ID - this logic is taken from original account.getRoutingPeerRoutes
	newPeerRoute.Peer = peerID
	// Store peer.Key for consistency (was previously peerID, which is inconsistent)
	newPeerRoute.Peer = peer.Key

[sonarqubecloud]

Quality Gate failed

Failed conditions
25 New issues
25 New Code Smells (required ≤ 0)

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