[codex] Add NCC transparency moderation case pipeline

[mashbean]

Summary

• Adds the moderation case data model, review/update mutation, report linkage, and notification/ledger hooks needed for NCC complaint and remedy tracking.
• Adds transparency metrics export support, including optional private external aggregate input for government, privacy, policy, model, and recommendation change metrics.
• Adds documentation and tests for the aggregate export shape and low-count privacy guardrails.

Validation

• Passed: npm run build
• Passed: focused Jest with temporary local Postgres on 5432: systemService, transparencyService, Community Watch utility tests, and types/__test__/2 system/comment suites.
• Note: the focused Jest run emitted expected local warnings for missing Stripe secret and Redis on 6379, but exited 0.

[codecov]

Codecov Report

❌ Patch coverage is 90.42017% with 57 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.57%. Comparing base (89f67f5) to head (d3c25e4).
⚠️ Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/connectors/commentService.ts	83.00%	15 Missing and 2 partials ⚠️
src/connectors/systemService.ts	83.50%	15 Missing and 1 partial ⚠️
src/connectors/transparencyService.ts	94.26%	15 Missing and 1 partial ⚠️
...ons/20260619090000_create_moderation_case_table.js	93.93%	4 Missing ⚠️
src/queries/system/report.ts	86.66%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4865      +/-   ##
===========================================
+ Coverage    73.12%   73.57%   +0.45%     
===========================================
  Files         1081     1084       +3     
  Lines        21644    22229     +585     
  Branches      4735     4896     +161     
===========================================
+ Hits         15828    16356     +528     
- Misses        5339     5392      +53     
- Partials       477      481       +4     

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