feat: add FinCall financial collections app

apps/python/fincall/README.md

@@ -0,0 +1,105 @@
+# FinCall
+
+AI-powered financial operations phone agent for overdue invoice follow-up using CALL-E.
+
+## What it does
+
+FinCall helps finance teams prioritize overdue invoices and conduct structured payment follow-up calls.
+
+The workflow is:
+
+1. Load overdue invoices
+2. Calculate collection priority
+3. Select an invoice
+4. Initiate an authorized CALL-E phone call
+5. Extract payment status and expected payment date
+6. Store the call outcome
+7. Recommend the next finance action
+
+## Features
+
+- Multiple overdue invoices
+- Collection prioritization
+- CALL-E outbound phone calls
+- Structured payment-status extraction
+- Expected payment-date extraction
+- Call evidence
+- Persistent call history
+- Recommended next actions
+- Streamlit dashboard
+
+## Setup
+
+Install the dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+Create a .env file:
+
+```bash
+CALLE_API_KEY=your_api_key
+```
+
+Run the application:
+
+```bash
+streamlit run app.py
+```
+
+## Credentials
+
+The CALL-E API key must be provided through the `CALLE_API_KEY` environment variable.
+
+Never commit API keys, credentials, or other secrets.
+
+## Phone numbers
+
+The example invoice data uses masked phone numbers.
+
+For live testing, replace the example phone number with a phone number that you are authorized to call.
+
+Do not use unauthorized or third-party phone numbers.
+
+## Side effects
+
+Live mode places a real outbound phone call through CALL-E.
+
+A phone call is initiated only when the operator explicitly presses the call button.
+
+Review the selected invoice and recipient before initiating a live call.
+
+## Cancellation and follow-up
+
+FinCall does not automatically initiate recurring calls.
+
+If a call requires follow-up, the previous outcome is displayed so that the operator can decide what action to take.
+
+Any additional call should be explicitly initiated by the operator.
+
+## Preview / demo behavior
+
+The invoice prioritization and dashboard workflow can be reviewed without placing a phone call.
+
+Live phone execution occurs only when the operator explicitly initiates the CALL-E action.
+
+## Safety
+
+- Do not commit credentials or API keys.
+- Use authorized phone numbers only.
+- Example data uses masked phone numbers.
+- Review call outcomes before taking consequential financial action.
+- FinCall does not automatically make recurring collection calls.
+
+## Project structure
+
+```text
+fincall/
+├── app.py
+├── fincall.py
+├── requirements.txt
+├── README.md
+└── data/
+    └── invoices.example.json
+```