docs: fix helper example links

[ynachiket]

• I understand that this repository is auto-generated and my pull request may not be merged

Changes being requested

Fix two stale links in helpers.md that still point to removed examples/function-call-helpers*.ts files. The links now point to the existing examples/tool-call-helpers.ts and examples/tool-call-helpers-zod.ts files.

Additional context & links

Validation:

• Confirmed examples/tool-call-helpers.ts exists
• Confirmed examples/tool-call-helpers-zod.ts exists
• Confirmed helpers.md no longer references examples/function-call-helpers*.ts
• git diff --check
• npm exec --yes --package prettier@3.7.1 -- prettier --check helpers.md

[HAYDEN-OAI]

@ynachiket thanks for catching these stale links and sending such a tidy fix. really appreciate your patience while we brought the branch current. merging now! 💚