System Health Digest Service

Problem Description

An operations team at a SaaS company runs a daily health digest that summarizes all system events from the past 24 hours and sends a report to the engineering leadership team. The current digest generator has a flaw: it filters out "noisy" recurring errors to keep the report readable, which has caused the leadership team to miss ongoing degradations. Last month, a payment integration was silently failing for 14 hours before someone noticed — it never appeared in the digest because it was filtered as a "known flapping issue."

The team wants a Python module that generates a health digest from a list of system events, but with a strict policy on what can and cannot be omitted. The module will replace the existing filter-happy generator and must ensure that certain categories of unresolved issues always appear in the output regardless of how often they've been seen.

Output Specification

Write a Python module digest_generator.py with a generate_digest(events: list) -> dict function that:

• Processes a list of event dictionaries
• Returns a digest dictionary structured for reporting
• Implements a clear inclusion/exclusion policy based on severity

Also write a generate_digest_demo.py script that:

• Creates a sample list of at least 6 events (mix of resolved, unresolved, different severity levels)
• Calls generate_digest() and writes the result to digest_output.json

Include a DIGEST_POLICY.md file explaining what appears in the digest and what may be omitted.