[ADMIN-001] Add admin moderation dashboard

[chev0004]

Outline

Summary

Adds the admin moderation dashboard: a report queue with reporter and reported-user context, moderation actions (dismiss, warn, hide profile, suspend, ban, plus reversals), a persistent audit log, and enforcement so hidden profiles leave public surfaces and suspended or banned users lose access to protected APIs.

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Changes & Enhancements

• Type of Change:
  • Feature
  • Bugfix
  • Refactor
  • Chore
• Changes:
  • (Database):
    • Add suspended_until and banned_at to users, hidden_by_moderation to profiles.
    • Add moderation_actions audit table and moderation_action enum.
    • Add warning notification kind.
  • (Server):
    • Add src/db/moderation.ts with report queue, audit log, and moderation state helpers.
    • Exclude hidden, banned, and suspended profiles from discovery, search-by-id, and public profile queries.
    • Add getActiveUser and use it in profile, bump, report, block, saved, settings, onboarding, and notifications APIs so restricted users get 401.
    • Add admin-only POST /api/admin/moderation applying actions to a report's target and logging every action.
  • (Admin UI):
    • Add /[lang]/admin route, guarded by the existing POLYCORD_ADMIN_USER_IDS allowlist, with the report queue, per-report action buttons, moderation state chips, and the audit log.
  • (Inbox):
    • Warn action creates a warning notification; the inbox renders moderation warning copy for all users.
  • (i18n):
    • Add Admin section and inbox warning copy to en and ja.

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Page / App Changes

Affected Next.js Routes (Local):

• /[lang]/admin (new admin moderation dashboard)
• /[lang] (discovery excludes moderated profiles)

Before (Screenshot)

After (Screenshot)

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Component / Storybook Changes

Affected Storybook Components (Local):

Before (Screenshot)

After (Screenshot)

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Not Doing

• Suspend duration is fixed at 7 days in the UI; the API already accepts 1 to 90 days for later controls.

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Other (Remarks)

This PR and #86 each add a migration numbered 0012 on independent branches. Whichever merges second needs drizzle/meta/_journal.json reconciled (rename one migration to 0013 and update its journal entry).

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Checklists

• Code is well-documented (comments, JSDoc, etc.).
• Existing comments were updated as needed.
• No out-of-scope changes are included.
• Write TODO comments where future work is required.
• Removed unnecessary debug code (e.g., console.log, debugger).
• Self-reviewed and tested locally.