docs(heartbeat): mark integration as unsupported

[TheRealAgentK]

Summary

Marks the Heartbeat (heartbeat.chat) integration as unsupported so users can see at a glance that it is no longer maintained.

Changes

• README.md — adds an ⚠️ Unsupported callout under the Heartbeat heading and prefixes the entry with [UNSUPPORTED].
• heartbeat/README.md — adds a prominent ⚠️ Status: Unsupported blockquote at the top explaining the integration is no longer maintained, not covered by CI/validation, and used at the user's own risk.

No code changes — documentation only.

Closes #319

[github-actions]

🔍 Integration Validation Results

Commit: 14e23bb9e3cb854dd083fe17dcd149be76ecafc7 · docs(heartbeat): mark integration as unsupported
Updated: 2026-05-12T04:12:04Z

Changed directories: heartbeat

Check	Result
Structure	⚠️ Passed with warnings
Code	⚠️ Passed with warnings
Tests	⚠️ Passed with warnings
README	✅ Passed
Version	✅ Passed

⚠️ Structure Check output

Validating 1 integration(s)...

============================================================
Integration: heartbeat
============================================================

Warnings (1):
  ⚠️ SDK version 1.0.2 is deprecated — upgrade to autohive-integrations-sdk~=1.1.1 or later

============================================================
SUMMARY
============================================================
Integrations validated: 1
Total errors: 0
Total warnings: 1

⚠️ Validation passed with warnings - please review

⚠️ Code Check output

[notice] A new release of pip is available: 26.0.1 -> 26.1.1
[notice] To update, run: pip install --upgrade pip
----------------------------------------
Checking: heartbeat
----------------------------------------

📦 Installing dependencies...

🐍 Checking Python syntax...
   ✅ Syntax OK

📥 Checking imports...
   ✅ Imports OK

📄 Checking JSON files...
   ✅ JSON files OK

🔍 Linting with ruff...
   ✅ Lint OK

🎨 Checking formatting with ruff...
   ✅ Formatting OK

🔒 Scanning for security issues with bandit...
   ✅ Security OK

🛡️ Checking dependencies for vulnerabilities with pip-audit...
   ✅ Dependencies OK

🔗 Checking config-code sync...
   ⚠️  Action 'create_heartbeat_comment': parameter 'parent_id' is optional in schema but accessed with inputs["parent_id"] (will raise KeyError if not provided)
   ⚠️  Action 'create_heartbeat_comment': parameter 'user_id' is optional in schema but accessed with inputs["user_id"] (will raise KeyError if not provided)
   ⚠️  Action 'create_heartbeat_thread': parameter 'user_id' is optional in schema but accessed with inputs["user_id"] (will raise KeyError if not provided)
   ✅ Config-code sync OK

🔄 Checking fetch patterns...
   ✅ Fetch patterns OK

========================================
✅ CODE CHECK PASSED
========================================

⚠️ Tests Check output

⚠️  No unit tests (test_*_unit.py) found in: heartbeat
⚠️  No unit tests to run

✅ README Check output

========================================
✅ README CHECK PASSED
========================================

✅ Version Check output

✅ heartbeat: No version bump needed (only tests/docs changed)

========================================
✅ VERSION CHECK PASSED
========================================