chore: rename Dark Matter references to MDK

[erskingardner]

What changed

The upstream library moved from marmot-protocol/darkmatter to marmot-protocol/mdk. This is the cosmetic rename pass in goggles to match:

• Docs prose: "Dark Matter" → "MDK" in README.md, docs/api-v1.md, and all mentions in docs/audit-debugging-platform-prd.md (including the "MDK Audit Data Gaps" heading, and one grammar fix: "a Dark Matter emitted" → "an MDK-emitted").
• Fixtures: the recorder_started event in all three fixtures/sample-audit-log-*.jsonl files now says "recorder":"mdk".
• Seed data + tests: "recorder": "darkmatter" → "mdk" in forensics/seed_data.py and forensics/tests.py, and the example upload user agent DarkMatter/1.2.3 → MDK/1.2.3.

Why

Keeps sample data, seeded dev environments, and docs consistent with the renamed library so new contributors don't chase a name that no longer exists.

Notes for reviewers

• No behavior change. Ingestion copies the recorder value as a free-form string and nothing filters or asserts on it; the JSON schema types it as a plain string. Old uploads with "recorder": "darkmatter" remain valid and display as-is.
• "recorder": "mdk" is the assumed new emitter string — if the mdk library actually stamps something else, updating fixtures is a one-line follow-up.
• Still open (intentionally not in this PR): confirm mdk did not change the schema_version string away from marmot-forensics-audit/v2. If it did, SUPPORTED_AUDIT_SCHEMA_VERSIONS in forensics/ingest.py needs the new value or uploads will be quarantined.
• Verified with just check: 199 tests pass, ruff lint/format clean, no migration drift.

🤖 Generated with Claude Code

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Summary by CodeRabbit

• Documentation

  • Updated product and API docs to use “MDK” terminology consistently.
  • Clarified audit/debugging guidance and rollout notes with the new naming.

• Bug Fixes

  • Aligned sample audit-log data with the current recorder name.
  • Updated test-backed examples and browser user-agent text to match MDK branding.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: cd54793e-41e8-4192-8cac-0d1dc08644a3

📥 Commits

Reviewing files that changed from the base of the PR and between 72e7356 and 85959fa.

📒 Files selected for processing (8)

• README.md
• docs/api-v1.md
• docs/audit-debugging-platform-prd.md
• fixtures/sample-audit-log-acme-dana.jsonl
• fixtures/sample-audit-log-trailhead-maya.jsonl
• fixtures/sample-audit-log-trailhead-theo.jsonl
• forensics/seed_data.py
• forensics/tests.py

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Walkthrough

Renames "Dark Matter"/"darkmatter" references to "MDK"/"mdk" throughout README, API and PRD documentation, JSONL audit-log fixtures, seed data scripts, and test files, including the recorder field value and HTTP_USER_AGENT header strings used in tests.

Changes

Dark Matter to MDK Rename

Layer / File(s)	Summary
Documentation terminology updates README.md, docs/api-v1.md, docs/audit-debugging-platform-prd.md	Replaces "Dark Matter" wording with "MDK" across the overview, API convergence-run description, and multiple PRD sections (audience, background, data modes, convergence state machine, data gaps, rollout phases, decisions, open questions, and risks).
Fixture and seed data recorder value update fixtures/sample-audit-log-*.jsonl, forensics/seed_data.py	Changes the recorder/kind.recorder field value from "darkmatter" to "mdk" in sample JSONL fixtures and the seed data script's recorder_started event.
Test data recorder and user-agent updates forensics/tests.py	Updates recorder_started event recorder values and HTTP_USER_AGENT header strings from Dark Matter to MDK across multiple test fixtures and assertions.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• marmot-protocol/goggles#114: Introduced the original PRD with "Dark Matter" terminology and audit-data-mode/recorder wording that this PR renames to MDK.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: renaming Dark Matter references to MDK across docs, fixtures, seed data, and tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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• Commit on current branch

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• Create PR with unit tests
• Commit unit tests in branch claude/vigilant-chandrasekhar-83f950

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[stage-review]

Ready to review this PR? Stage has broken it down into 3 individual chapters for you:

	Title
1	Update documentation to reflect MDK renaming
2	Migrate sample fixtures and seed data
3	Update test assertions and user agents

_{Chapters generated by Stage for commit 85959fa on Jul 4, 2026 12:53pm UTC.}