docs(identity): per-request front-end origin for auth e-mail links

src/content/docs/changelog/index.mdx

@@ -1,6 +1,6 @@
 ---
 title: Overview
-lastUpdated: 2026-06-20
+lastUpdated: 2026-07-02
 description: Release notes and version history for fullstackhero.
 sidebar:
   order: 1
@@ -11,6 +11,10 @@ seo:
 
 Notable changes to the kit, newest first.
 
+## 2026-07-02
+
+- **Identity: password-reset and e-mail-confirmation links now point at the front-end that made the request.** The reset link was built from a single configured `OriginOptions.OriginUrl` — which points at the API and ships empty in production, so `forgot-password` threw `Origin URL is not configured` — and the confirmation link was built from the request host and pointed straight at the API's `GET /confirm-email` route. Neither could target the right SPA when the kit serves more than one front-end (the admin console and the tenant dashboard on different origins). The Identity module now resolves the link's base URL from the request `Origin` header, validated against `CorsOptions.AllowedOrigins`: each user gets a link back to the app they started from, and — because forgot-password is anonymous — a forged or unlisted `Origin` is rejected rather than turned into a link inside an e-mail. The confirmation e-mail now lands on the SPA `/confirm-email` page (which then calls the API) instead of the raw API route. **Action for deployments:** list your SPA origins in `CorsOptions:AllowedOrigins` — the dev config now ships `http://localhost:5173` and `http://localhost:5174`; with the list empty these flows are rejected. `OriginOptions:OriginUrl` keeps its role as the API's own public base (avatar URLs). See [#1323](https://github.com/fullstackhero/dotnet-starter-kit/pull/1323).
+
 ## 2026-06-20
 
 - **The `fsh` CLI and `dotnet new` template are now on NuGet as stable `10.0.0`.** The two distribution packages that 10.0.0 had been waiting on have shipped: `FullStackHero.CLI` (install with `dotnet tool install -g FullStackHero.CLI` — no more `--prerelease`) and `FullStackHero.NET.StarterKit` (`dotnet new install FullStackHero.NET.StarterKit`). Because `fsh new` scaffolds *from* that template, the one-command flow is now end-to-end: `dotnet tool install -g FullStackHero.CLI && fsh new MyApp` produces a fully renamed project — unique JWT signing key, generated Docker secrets, `npm install` run, initial commit on `main`. The [Install](/docs/getting-started/install/) and [CLI](/docs/cli/) pages now lead with the CLI as the recommended path; `git clone` and the GitHub template remain available for reading the source or zero-install runs. See the [10.0.0 release](https://github.com/fullstackhero/dotnet-starter-kit/releases/tag/10.0.0).

src/content/docs/modules/identity.mdx

@@ -1,6 +1,6 @@
 ---
 title: Identity module
-lastUpdated: 2026-06-11
+lastUpdated: 2026-07-02
 description: JWT bearer + refresh tokens, ASP.NET Identity with roles + permissions, user groups, operator impersonation, two-factor TOTP, sessions, and password-policy enforcement.
 sidebar:
   label: Identity
@@ -149,6 +149,10 @@ endpoints.MapPost("/users", handler)
 
 All 51 endpoints are under `/api/v1/identity/`. The rate-limited `auth` policy covers `POST /token/issue`, `POST /token/refresh`, `GET /confirm-email`, `POST /users/{id}/resend-confirmation-email`, `POST /forgot-password`, `POST /reset-password`, and `POST /self-register`. Full table:
 
+<Callout type="note" title="Where reset & confirmation e-mails point">
+The `forgot-password` and registration e-mails link back to the **front-end that made the request**: the Identity module resolves the link's base URL from the request `Origin` header, validated against `CorsOptions.AllowedOrigins`. With more than one SPA each user gets a link to the app they started from, and a forged or unlisted origin is rejected rather than e-mailed. The confirmation link lands on the SPA `/confirm-email` page (which then calls `GET /confirm-email`), not the API route directly. List your SPA origins in `AllowedOrigins` for these flows to work — see [CORS & headers](/docs/security/cors-and-headers/).
+</Callout>
+
 | Verb | Route | What it does |
 |---|---|---|
 | POST | `/token/issue` | Login |

src/content/docs/security/cors-and-headers.mdx

@@ -1,6 +1,6 @@
 ---
 title: CORS & security headers
-lastUpdated: 2026-06-11
+lastUpdated: 2026-07-02
 description: CORS-before-HTTPS-redirect ordering, the SignalR-credentialed-CORS gotcha, and the production security headers the kit emits by default.
 sidebar:
   label: CORS & headers
@@ -54,6 +54,12 @@ Pipeline order (relevant slice):
 6. ...
 ```
 
+## Front-end origin for auth e-mail links
+
+`AllowedOrigins` does double duty. Besides the CORS policy, it is the allowlist the Identity module validates the request `Origin` header against when it builds a link that lands on a front-end — the password-reset and e-mail-confirmation e-mails. Each link is built from the origin the request actually came from, so when you serve more than one SPA (say an admin console on one origin and a tenant app on another) every user gets a link back to the app they started from, not a single hard-coded URL.
+
+Because forgot-password is anonymous, this validation is a security boundary: a forged `Origin` header that is not in `AllowedOrigins` is rejected rather than turned into a link inside an e-mail. The check always runs against `AllowedOrigins`, independently of `AllowAll` — so for these links to resolve you must list your SPA origins explicitly, even in dev. A request whose `Origin` isn't allow-listed fails instead of e-mailing a link to the wrong host. (`OriginOptions:OriginUrl` remains the API's own public base, used for API-served assets such as avatar URLs — it is not the front-end link base.)
+
 ## Why not AllowAnyOrigin for SignalR
 
 CORS spec says: when a response has `Access-Control-Allow-Credentials: true`, the `Access-Control-Allow-Origin` must be an explicit origin, not `*`. SignalR's negotiate request is credentialed (it carries `Cookie` or the JWT via `accessTokenFactory`'s query-param fallback). With `AllowAnyOrigin()`, the server emits `Allow-Origin: *`, which violates the spec — the browser silently refuses to use the response, and SignalR's `HubConnection` fails to start with a confusing CORS error.
@@ -129,7 +135,7 @@ The cookie should be HttpOnly (no JS access — limits XSS impact), Secure (HTTP
 ## Common mistakes
 
 - **Setting `AllowAll = true` in production.** CORS exists to give browsers a sanity check on cross-origin calls. Opening to the world removes the check (it doesn't directly compromise auth — auth still gates the request — but it removes the browser-enforced "is this site allowed to call you?" layer).
-- **Forgetting to fill `AllowedOrigins` in production.** With `AllowAll: false` and no origins, CORS isn't mounted — your React apps on other origins will get blocked by the browser. The symptom is "works in Postman, fails in the browser".
+- **Forgetting to fill `AllowedOrigins` in production.** With `AllowAll: false` and no origins, CORS isn't mounted — your React apps on other origins will get blocked by the browser. The symptom is "works in Postman, fails in the browser". It also breaks password-reset and e-mail-confirmation links: the Identity module validates the request `Origin` against this same list to pick which front-end the e-mailed link points to, so an origin that isn't listed makes forgot-password and registration reject the request instead of sending the e-mail.
 - **Missing HSTS.** Without HSTS, an attacker on the network can downgrade to HTTP for the first request. The kit emits it on HTTPS responses automatically; verify your proxy doesn't strip it.
 - **CSP that breaks the UI.** If a third-party widget breaks after tightening CSP, look at the browser console — CSP violations are logged. Add the needed origins to `ScriptSources`/`StyleSources`, don't disable the middleware.
 

src/content/docs/security/production-checklist.mdx

@@ -1,6 +1,6 @@
 ---
 title: Production security checklist
-lastUpdated: 2026-06-11
+lastUpdated: 2026-07-02
 description: Ten configuration items you must check before shipping fullstackhero to production. Skip none.
 sidebar:
   label: Production checklist
@@ -57,7 +57,7 @@ Adjust for your industry. Healthcare (HIPAA) and finance (PCI-DSS) tend to requi
 
 ## 3. Allowlist CORS origins
 
-`CorsOptions:AllowAll = true` (and the `SetIsOriginAllowed(_ => true)` policy it enables) is **dev only**. Production needs the explicit lists — and note that `appsettings.Production.json` ships `AllowedOrigins` empty, which means **no CORS middleware mounts at all** until you fill it in; your front-ends on other origins will be blocked by the browser. See [CORS & security headers](/docs/security/cors-and-headers/).
+`CorsOptions:AllowAll = true` (and the `SetIsOriginAllowed(_ => true)` policy it enables) is **dev only**. Production needs the explicit lists — and note that `appsettings.Production.json` ships `AllowedOrigins` empty, which means **no CORS middleware mounts at all** until you fill it in; your front-ends on other origins will be blocked by the browser. `AllowedOrigins` is also the allowlist the Identity module validates the request `Origin` against to build password-reset and e-mail-confirmation links, so if it doesn't list your SPA origins those flows are rejected and no e-mail is sent. See [CORS & security headers](/docs/security/cors-and-headers/).
 
 ```jsonc
 {