Fix/docs duplication and links

Created by: ihsraham

This PR addresses duplication issues in the core module API documentation and fixes broken links in the summary. It also ensures the codebase aligns with the recent 24-word seed phrase support update.

Changes

• Docs: Removed duplicate entries for getRandomSeedPhrase in sdk/core-module/api-reference.md.
• Docs: Fixed broken "Installation" and "Instantiation" links in SUMMARY.md, redirecting them to the unified getting-started.md.
• Docs: Cleaned up redundant commented-out code in sdk/get-started.md.

Checks

• Verified api-reference.md renders correctly without duplicate table rows or examples.
• Verified SUMMARY.md links point to existing files.
• Verified sdk/get-started.md content is clean and accurate.