feat(routes): add delivery estimate endpoint (rerun)

[ogulcan-gurcaglar]

Controlled re-run: tree is byte-identical to the pre-deploy probe branch, so discovery prompts hit the AI cache and only the confirmation stage differs.

[zeropath-ai-staging]

✅ No security or compliance issues detected. Reviewed everything up to b83be85.

Security Overview

• 🔎 Scanned files: 1 changed file(s)
• 🔗 Scan Link: https://staging.branch.zeropath.com/app/repositories/76e78572-4c4d-4c18-8702-81b7a5a6273c?scanId=62d3ff38-f769-491c-9cd7-e6d997c18500&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
New file addition	► routes/deliveryEstimate.ts     Add deliveryEstimate route for region-based ETA and note retrieval

[zeropath-ai-staging]

✅ No security or compliance issues detected. Reviewed everything up to b83be85.

Security Overview

• 🔎 Scanned files: 1 changed file(s)
• 🔗 Scan Link: https://staging.branch.zeropath.com/app/repositories/5eea4b94-6a72-403c-af68-60abe8a1d179?scanId=8a97cae5-abe4-4ff2-9569-0a04f101eaa9&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
New file addition	► routes/deliveryEstimate.ts     Add deliveryEstimate route for region-based ETA and note retrieval