Fix stale governance proposal alerts

[spalen0]

Summary

• fix Aave proposal monitor to alert only governance-executed proposals that still have pending payloads, using Aave governance cache API payload state across chains
• exclude cancelled proposals and fully executed payload sets like proposal 488, while including pending examples like proposal 489
• harden Maker, Fluid, and Compound proposal monitors around cache updates, Markdown escaping, payload validation, timeouts, and processing errors
• add focused proposal monitor regression tests

Verification

Aave Governance v3 state Executed = 4 means vote results were sent and payloads were created/queued, not necessarily that every payload has executed. The monitor now fetches governance-executed proposals from the subgraph, then checks Aave governance cache payload states and only reports proposals where at least one payload is not executed.

Local debug run updated /srv/cache/cache-id.txt to aave:489 with Telegram skipped by LOG_LEVEL=DEBUG.

Tests

• uv run --extra dev pytest tests/test_aave_proposals.py tests/test_fluid_proposals.py tests/test_maker_proposals.py tests/test_compound_proposals.py -q
• uv run ruff check aave/proposals.py fluid/proposals.py maker/proposals.py compound/proposals.py tests/test_aave_proposals.py tests/test_fluid_proposals.py tests/test_maker_proposals.py tests/test_compound_proposals.py