[$25 BOUNTY] [Python] Add log aggregator redaction summary report

[Soengkit]

Bounty: $25 (LT)

Area: tools/log_aggregator.py and docs/OPERATIONS.md

Current state: Log aggregation can process records, but audit reviewers do not get a compact summary of redactions and malformed records.

What's needed: Add a redaction summary report for log aggregation runs.

Acceptance criteria:

• Text and JSON summary output include processed, malformed, and redacted-field counts
• Source file names are included without exposing raw secret values
• Valid, malformed, and secret-like fixture inputs are covered
• Existing log aggregation output remains compatible by default
• Operations docs include the report command and expected output

Required validation:

• Run python3 build.py
• Include the generated diagnostic .logd artifact from diagnostic/build-XXX.logd in the PR; also include diagnostic/build-XXX.json if present
• Use .github/pull_request_template.md for your submission

[Rachaelisa]

/claim #2

I'd like to take this on! Reviewing the repository right now and will submit a PR shortly.