Add tests for MCP and MEMORY context source types

[harshvardhan60792]

Fixes #20

Added test coverage for ContextSource.MCP and ContextSource.MEMORY in test_models.py (source parsing) and test_trail.py (logging, query filtering, summary counting, and JSON export).

Testing: Added unit tests in test_models.py and test_trail.py; verified with pytest (131 passed) and ruff.

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What does this PR do?

Checklist

• Tests added/updated for the change
• ruff check src/ tests/ passes
• ruff format --check src/ tests/ passes
• mypy src/provena/ passes
• pytest passes with no failures
• CHANGELOG.md updated (if user-facing change)

Related Issues

[rajfirke]

Thanks @harshvardhan60792 — the tests cover the right cases and CI failures are just a ruff format issue, not test failures. Two lines in test_trail.py exceed the line-length limit:

r2 = memory_trail.log("explicit enum mcp", source=ContextSource.MCP, source_name="github")
r2 = memory_trail.log("working memory", source=ContextSource.MEMORY, source_name="working")

Run ruff format tests/test_trail.py locally — it'll split those two lines automatically and CI will go green. Everything else looks good to go.

[harshvardhan60792]

Thanks for the pointer @rajfirke! Ran
uff format\ on \ ests/test_trail.py\ to split those two lines and pushed the update. CI should be green now.