feat(api): tenant-scoped sender and provider configuration

[patoperpetua]

Summary

• Add TENANT_EMAIL_CONFIG_BY_ID (App Configuration: app:email:tenantConfigById) to resolve per-tenant/environment fromAddress, fromDisplayName, and replyTo server-side, merged with platform EMAIL_FROM_* defaults.
• Wire send.ts to use resolved tenant sender identity; request-body sender/reply-to fields are ignored. Missing tenant config returns stable TENANT_CONFIG_NOT_FOUND.
• Support optional per-tenant providerAccount via TENANT_PROVIDER_ACCOUNT_SECRETS (Key Vault-backed env var references). Append troubleshooting row for the new error code.

Closes #35

Test plan

• pnpm -r --if-present run test passes
• Tenant sender fields applied from config (send.tenant-sender.spec.ts)
• Request-body sender spoofing has no effect
• Missing tenant config returns TENANT_CONFIG_NOT_FOUND without leaking another tenant's sender
• Platform defaults apply only for unset tenant fields
• Provider credentials not exposed in error responses or logs

Made with Cursor

Summary by CodeRabbit

• New Features

  • Added tenant-specific email sender, reply-to, and provider credential configuration.
  • Tenant settings override request values, while platform defaults fill missing fields.
  • Provider credentials and account identifiers are excluded from responses, logs, and errors.

• Bug Fixes

  • Added a clear service-unavailable error when tenant email configuration is missing or invalid.

• Documentation

  • Updated troubleshooting guidance for tenant configuration errors.

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ℹ️ Recent review info

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Review profile: CHILL

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Run ID: d41875ce-416b-46d2-955d-736a45d9856a

📥 Commits

Reviewing files that changed from the base of the PR and between c26c379 and 3048e82.

📒 Files selected for processing (3)

• apps/api/src/functions/send.tenant-sender.spec.ts
• apps/api/src/tenant/tenant-email-config.spec.ts
• apps/api/src/tenant/tenant-email-config.ts

🚧 Files skipped from review as they are similar to previous changes (3)

• apps/api/src/tenant/tenant-email-config.spec.ts
• apps/api/src/tenant/tenant-email-config.ts
• apps/api/src/functions/send.tenant-sender.spec.ts

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📝 Walkthrough

Walkthrough

The API resolves tenant-specific sender fields and provider tokens from environment-backed configuration. The send handler applies these values server-side, returns a typed 503 error for missing configuration, and prevents credential disclosure.

Changes

Tenant email configuration

Layer / File(s)	Summary
Configuration resolution and validation apps/api/src/tenant/..., apps/api/src/config/app-configuration.ts, .env.example, apps/api/src/tenant/tenant-email-config.spec.ts	Tenant and environment email settings are parsed, validated, cached, merged with platform defaults, and resolved with provider tokens.
Send-handler integration apps/api/src/functions/send.ts, packages/post-kit-email/src/providers/create-email-provider.ts, packages/post-kit-types/src/send.ts, packages/post-kit-types/src/index.spec.ts	The send flow uses resolved tenant sender fields and optional provider tokens. Missing configuration maps to TENANT_CONFIG_NOT_FOUND and HTTP 503.
Send-flow validation apps/api/src/functions/send*.spec.ts, docs/operations/troubleshooting.md	Tests cover sender precedence, missing configuration, environment isolation, secret redaction, and existing send outcomes. Troubleshooting documentation describes the new error.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to 3048e

The PR adds tenant-scoped sender and provider configuration with the described fallback and error behavior; no actionable merge-blocking risk remains after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant Request
  participant SendHandler
  participant resolveTenantEmailConfig
  participant Environment
  participant EmailProvider
  Request->>SendHandler: authenticated send request
  SendHandler->>resolveTenantEmailConfig: resolve tenant email settings
  resolveTenantEmailConfig->>Environment: read tenant config and provider token
  resolveTenantEmailConfig-->>SendHandler: return sender fields and apiToken
  SendHandler->>EmailProvider: send email with resolved sender

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 11.54% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 26 functions across 11 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the primary change: tenant-scoped sender and provider configuration for the API.
Description check	✅ Passed	The description includes the linked issue, a clear summary, and relevant test coverage. It omits the template's detailed setup, step-by-step expected results, and feedback focus sections, but the core…
Linked Issues check	✅ Passed	The implementation satisfies the linked issue objectives [#35]: it resolves tenant-scoped sender fields and optional provider accounts server-side, ignores request-body sender fields, applies platform…
Out of Scope Changes check	✅ Passed	All changes support the linked issue [#35]. The configuration mappings, resolver, send-handler wiring, provider override, error code, documentation, and tests are directly related to tenant-scoped sen…

Full details: Description check

Explanation

The description includes the linked issue, a clear summary, and relevant test coverage. It omits the template's detailed setup, step-by-step expected results, and feedback focus sections, but the core information is complete.

Full details: Linked Issues check

Explanation

The implementation satisfies the linked issue objectives [#35]: it resolves tenant-scoped sender fields and optional provider accounts server-side, ignores request-body sender fields, applies platform defaults only to unset fields, returns TENANT_CONFIG_NOT_FOUND for missing configuration, avoids credential and account-identifier leakage, and uses Azure-native configuration without database changes.

Full details: Out of Scope Changes check

Explanation

All changes support the linked issue [#35]. The configuration mappings, resolver, send-handler wiring, provider override, error code, documentation, and tests are directly related to tenant-scoped sender and provider configuration.

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[patoperpetua]

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Actionable comments posted: 1

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Inline comments:
In `@apps/api/src/tenant/tenant-email-config.ts`:
- Around line 229-232: Update the parseOptionalString call in the tenant
provider account configuration parsing flow to use a generic field description
that does not interpolate accountId, and add a regression test covering the send
response body to verify the provider account identifier is not exposed.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 8a056035-2f1d-475b-8d7e-567533dbe0ff

📥 Commits

Reviewing files that changed from the base of the PR and between a2dfa4e and c26c379.

📒 Files selected for processing (13)

• .env.example
• apps/api/src/config/app-configuration.ts
• apps/api/src/functions/send.security.spec.ts
• apps/api/src/functions/send.spec.ts
• apps/api/src/functions/send.tenant-sender.spec.ts
• apps/api/src/functions/send.ts
• apps/api/src/tenant/index.ts
• apps/api/src/tenant/tenant-email-config.spec.ts
• apps/api/src/tenant/tenant-email-config.ts
• docs/operations/troubleshooting.md
• packages/post-kit-email/src/providers/create-email-provider.ts
• packages/post-kit-types/src/index.spec.ts
• packages/post-kit-types/src/send.ts

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