docs(GRO-106): 10DLC pilot registration runbook (#375)

* docs(GRO-106): 10DLC pilot registration runbook

Co-Authored-By: Paperclip <noreply@paperclip.ing>

* fix(GRO-106): address QA review feedback

- Change business_vertical from FINANCE_INSURANCE_BANKING to PROFESSIONAL_SERVICES
- Fix broken internal issue links (GRO-106, GRO-981) to plain text
- Add owner stamp alongside last-updated date
- Fix phone placeholder in SQL and API example to use +1XXXXXXXXXX
- Add trailing newline to both runbook files

Co-Authored-By: Paperclip <noreply@paperclip.ing>

---------

Co-authored-by: Chris Farhood <chris@farhood.org>
Co-authored-by: Paperclip <noreply@paperclip.ing>

docs/runbooks/README.md

@@ -0,0 +1,11 @@
+# GroomBook Runbooks
+
+Operational runbooks for GroomBook staff and operators.
+
+| Runbook | Description | Status |
+|---------|-------------|--------|
+| [10DLC Pilot Registration](./10dlc-pilot-registration.md) | Register a pilot grooming business as an A2P 10DLC brand + campaign on Telnyx | Active |
+
+---
+
+_To add a runbook, create a markdown file in this directory and update this table._