docs(examples): fix hello world implementation links

[shaurya35]

Description

• Update the Hello World implementation links to point to the current src/index.tsentrypoint.
• Remove references to the obsolete src/actors.ts and src/server.ts files.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Confirmed that the obsolete source paths no longer appear in the README.
• No automated tests were run because this is a documentation-only change.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[the-company-company]

🔵 1 low-severity finding

_{Reviewed commit cb3d791.}

[the-company-company]

✅ No issues found

_{Reviewed commit 794f528.}

[shaurya35]

@NathanFlurry @jog1t, pinging once on this