Restructure SDK build section

[stwiname]

Restructures the build section of the SDK to be much clearer and easier to follow.

This also greatly de-duplicates a lot of pages that had minor differences for chain specifics

[Copilot]

Pull Request Overview

This PR restructures the build section of the SDK to improve organization and reduce duplication by consolidating chain-specific documentation. The changes update numerous link references throughout quickstart guides and documentation files to reflect the new directory structure.

• Updates file paths from individual chain documentation to consolidated chain-specific folders
• Consolidates mapping and manifest documentation under new organizational structure
• Removes duplicate mapping files for various EVM-compatible chains (Polygon, Optimism, Gnosis, Flare, BSC, Avalanche, Arbitrum)

Reviewed Changes

Copilot reviewed 124 out of 126 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
Multiple quickstart snippet files	Updated documentation links to point to new chain-specific manifest and mapping paths
Multiple manifest files	Removed duplicate chain-specific manifest files (Stellar, Starknet, Solana, Polygon, etc.)
Multiple mapping files	Removed duplicate EVM chain mapping files that had minor differences
New mapping-functions structure	Introduced new organized structure for mapping functions documentation
Store and sandbox documentation	Restructured under new mapping-functions/sandbox hierarchy

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[Copilot]

The link points to a manifest documentation file but the text refers to 'Mappings' and 'mapping functions'. This should point to the mapping functions documentation, not the manifest documentation.

Suggested change

	Check out our [Mappings](../../build/manifest/chain-specific/cosmos.md) documentation and get information on the mapping functions in detail.
	Check out our [Mappings](../../build/mappings/chain-specific/cosmos.md) documentation and get information on the mapping functions in detail.