Sprint 63: Discord Feedback Notifications (One-Way Webhook)

Decisions

Context: Need to send Discord notifications to admins when feedback is created. Choice needed between Gateway (proxy) vs Identity (storage owner).
Choice: Place DiscordWebhookService in the Identity service. Since Identity is the feedback storage owner, webhooks should also be sent from the same service.
Alternatives: Gateway sends webhook after Identity response — rejected as it adds business logic to the proxy layer.
Code Paths: services/identity/src/discord/discord-webhook.service.ts

Context: Currently only one-way webhook is needed, but Discord bot interaction features are planned for future expansion.
Choice: Separate as discord/ independent module. DiscordModule exports DiscordWebhookService.
Alternatives: Implement directly inside feedback module — rejected as refactoring would be needed on expansion.
Code Paths: services/identity/src/discord/discord.module.ts

Context: Discord Embed fields format has poor readability. Table format is not supported by Discord.
Choice: Code block (message body) + bold/inline code (metadata) combination in description. No emojis.
Alternatives: (A) fields list — poor visibility, (B) code block table — no link/color support, (C) image trick — external dependency
Code Paths: services/identity/src/discord/discord-webhook.service.ts

Context: Incomplete Discord webhook stubs existed in ci.yml notify job and alertmanager.yaml.
Choice: Remove CI Discord step (keep Grafana annotation), convert alertmanager receiver to null.
Alternatives: Use existing stubs — rejected as structure differs and they are incomplete.
Code Paths: .github/workflows/ci.yml, infra/k3s/monitoring/alertmanager.yaml

Where: services/identity/src/discord/discord-webhook.service.ts, services/identity/src/feedback/feedback.service.ts
When to Reuse: When calling external services (webhooks, notifications, etc.) that should not affect the main business logic on failure. Log errors only with .catch() without propagating exceptions.

Where: services/identity/src/discord/discord-webhook.service.ts
When to Reuse: When an optional external integration service should not block service startup if env var is missing. Use warnedMissingUrl flag to prevent log spam.

Symptom: Identity test branches at 97.91% after first push, causing CI failure.
Root Cause: Non-Error throw case in err instanceof Error ? ... : String(err) branch not covered.
Fix: Added string throw test case to bring coverage to 98.43% (e29832e).