feat(dev): add credits dev tool on /profile

[IamCoder18]

Summary

Adds a companion "Add Credits" dev tool on /profile, mirroring the existing "Consume Credits" tool so devs can grant themselves credits without a real Stripe purchase or admin grant.

Changes:

• apps/web/src/app/api/dev/add-credits/route.ts (new) — dev-only POST that inserts a credit_transactions row (credit_category: 'dev-tools', is_free: true) and increments kilocode_users.total_microdollars_acquired, then calls forceImmediateExpirationRecomputation to bust the balance cache. Mirrors the auth/guard pattern in apps/web/src/app/api/dev/consume-credits/route.ts and the write pattern in apps/web/src/lib/promotionalCredits.ts:175-224, but bypasses promoCreditCategoriesByKey since this is not a real campaign.
• apps/web/src/components/dev/DevAddCreditsButton.tsx (new) — mirrors DevConsumeCreditsButton.tsx: amount input + Add button, router.refresh() on success, dev-mode guard.
• apps/web/src/app/(app)/profile/page.tsx — adds an "Add Credits" section above "Consume Credits" in the existing Development Tools card.

No DB migration. No new env vars. No changes outside apps/web/src/app/api/dev, apps/web/src/components/dev, and the /profile page.

Verification

• Visited /profile, entered an amount in the new "Add Credits" section, and submitted. Verified total_microdollars_acquired increases and the profile balance counter refreshes.

• Ran pnpm -w exec oxlint --config .oxlintrc.json on the changed files — 0 warnings, 0 errors.

Visual Changes

Reviewer Notes

• Endpoint is gated by process.env.NODE_ENV === 'development', same as the sibling consume-credits route, so it is unreachable in production.
• The credit_category literal 'dev-tools' is intentionally not registered in promoCreditCategoriesByKey, keeping it isolated from real campaigns.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Executive Summary

Reviewed the three-file dev-only Add Credits tool on /profile; it mirrors the existing consume-credits auth, write, and UI patterns with no high-confidence defects.

Files Reviewed (3 files)

• apps/web/src/app/(app)/profile/page.tsx
• apps/web/src/app/api/dev/add-credits/route.ts
• apps/web/src/components/dev/DevAddCreditsButton.tsx

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_{Review guidance: REVIEW.md from base branch main}

[IamCoder18]

Ready for review!