Auto-send proposal PDFs when HubSpot deals hit Proposal stage

Build me an agent workflow that automatically generates and sends a tailored proposal PDF the moment a HubSpot deal moves into the "Proposal" stage.

Trigger: a HubSpot webhook that fires on deal property change for the deal stage. The agent should only run when the new stage matches a configurable "proposal" stage ID (or stage label).

When triggered, the agent should:

1) Call HubSpot "Get Deal" to pull the deal by ID. Request the associated company and primary contact, and also pull associated line items. I need deal name, amount, close date, line item descriptions and prices, the company name, the company industry and segment fields, and the primary contact's first name, last name, and email.

2) Draft a one-page proposal narrative based on that context. The narrative should include an executive summary, scope of work, pricing summary (computed from line items and the deal amount), and a short standard terms section. Personalize the tone and the scope language based on the company's industry or segment so a SaaS company and a manufacturing company get noticeably different copy.

3) Render the proposal through PDF.co "Convert HTML Template to PDF" using a Handlebars-based proposal template I have saved in PDF.co. Use PDF.co "HTML Templates" to look the template up by name or ID so I can iterate on the template without redeploying. Pass the deal, company, contact, line items, and the drafted narrative as template variables.

4) Once the PDF URL comes back from PDF.co, send the proposal to the primary contact using Gmail "Send a Message". Include a short, friendly cover note signed by the deal owner and a link to the PDF. CC the deal owner.

5) Log the activity with HubSpot "Create Note", associated to the deal (and to the company and contact if easy), so the rep can see the proposal in the deal timeline. The note body should include the email subject, the recipient, a one-line summary of what was sent, and the PDF link.

Keep the qualifying stage, the proposal template ID, the cover email copy, and the "from" mailbox as configurable inputs so I can tune them without editing the workflow. If the deal is missing a primary contact email or has no line items, skip the email send, still create a note on the deal explaining what was missing, and exit cleanly.