feat: add product-aware deletion emails and subdomain deletion/downloads routes

- Extend DeletionForm with product discriminator and configurable cooldown cookie
- Extract env-free deletion email helpers into deletion-email.ts with Lineage/Nessa branding
- Make misc.sendDeletionRequestEmail mutation product-aware (subject, html content, cookie)
- Replace legacy /deletion/life-and-lineage page with 308 redirect to lineage subdomain
- Add Lineage and Nessa subdomain deletion route modules with shared content components
- Add Lineage downloads route modules with shared content
- Update privacy policy deletion link to lineage subdomain

src/server/api/routers/deletion-email.ts

@@ -0,0 +1,76 @@
+/**
+ * Pure helpers for the generalized account-deletion-request email flow
+ * (task 11).
+ *
+ * Extracted from `src/server/api/routers/misc.ts` so they can be unit-tested
+ * in `bun:test` WITHOUT importing `~/env/server` (which validates ~30 secrets
+ * at import time and is therefore un-runnable in a worktree without a
+ * populated `.env`). This mirrors the `page-head-meta.ts` / `nav-config.ts`
+ * testability pattern.
+ *
+ * `misc.ts` re-exports these for convenience; the deletion tRPC mutation
+ * consumes them directly.
+ */
+import { z } from "zod";
+
+/**
+ * Product whose account is being deleted. Drives email branding + the
+ * cooldown cookie name so per-product cooldowns don't interfere.
+ */
+export const DELETION_PRODUCT_SCHEMA = z.enum(["lineage", "nessa"]);
+export type DeletionProduct = z.infer<typeof DELETION_PRODUCT_SCHEMA>;
+
+/**
+ * Cooldown cookie name for a given product. Lineage keeps the legacy
+ * `deletionRequestSent` name so an in-flight cooldown from the old
+ * `/deletion/life-and-lineage` route is honored across the 308 redirect
+ * (no forced re-send). Nessa uses a distinct name so its cooldown is
+ * independent.
+ */
+export function deletionCookieName(product: DeletionProduct): string {
+  return product === "nessa"
+    ? "nessaDeletionRequestSent"
+    : "deletionRequestSent";
+}
+
+/** Branded copy for the deletion-request emails (operator + user-facing). */
+export interface DeletionEmailContent {
+  /** Email subject line (shared by operator + user emails). */
+  subject: string;
+  /** HTML body sent to michael@freno.me (the operator). */
+  operatorHtml: string;
+  /** HTML body sent to the requester (the user). */
+  userHtml: string;
+}
+
+/**
+ * Build the product-branded deletion-request email content.
+ *
+ * The operator email identifies the request name + requester email; the user
+ * email identifies the account being deleted + the 24h cancellation window.
+ * The `product` discriminator switches branding between Lineage (the original
+ * flow) and Nessa (task 11 — Nessa stores user data in its own Turso DB).
+ *
+ * `email` is interpolated verbatim into the HTML bodies. It has already been
+ * validated as a well-formed email by the tRPC input schema, and Sendinblue
+ * renders HTML bodies, so the value is not re-escaped here — matching the
+ * original Lineage implementation's behavior to avoid regressing the existing
+ * flow's email formatting.
+ */
+export function deletionEmailContent(
+  product: DeletionProduct,
+  email: string
+): DeletionEmailContent {
+  if (product === "nessa") {
+    return {
+      subject: "Nessa Acct Deletion",
+      operatorHtml: `<html><head></head><body><div>Request Name: Nessa Account Deletion</div><div>Request Email: ${email}</div></body></html>`,
+      userHtml: `<html><head></head><body><div>Request Name: Nessa Account Deletion</div><div>Account to delete: ${email}</div><div>You can email michael@freno.me in the next 24hrs to cancel the deletion, email with subject line "Account Deletion Cancellation". Your Nessa account row, workout / plan data, and community memberships will be removed.</div></body></html>`
+    };
+  }
+  return {
+    subject: "Life and Lineage Acct Deletion",
+    operatorHtml: `<html><head></head><body><div>Request Name: Life and Lineage Account Deletion</div><div>Request Email: ${email}</div></body></html>`,
+    userHtml: `<html><head></head><body><div>Request Name: Life and Lineage Account Deletion</div><div>Account to delete: ${email}</div><div>You can email michael@freno.me in the next 24hrs to cancel the deletion, email with subject line "Account Deletion Cancellation"</div></body></html>`
+  };
+}