Rebrand to INBUXA: product name, protocol greetings, sign-in page, calendar templates, logos, README

One branding module (types::brand!) supplies the name to every protocol
greeting, the HTTP realm, the startup banner, Received headers, the
user agent, the IMAP ID response and calendar PRODIDs. The sign-in and
calendar pages take ihasmail's palette and font and the INBUXA logo, and
calendar emails embed the INBUXA lockup. Default calendar and address book
names follow. Protocol identifiers (urn:stalwart:jmap, vnd.stalwart Sieve
extensions) and upstream copyright notices are unchanged.

crates/types/src/branding.rs

@@ -0,0 +1,39 @@
+/*
+ * SPDX-FileCopyrightText: 2026 John Coffey
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! The product's name, in one place.
+//!
+//! Every name the server shows people (protocol greetings, the HTTP sign-in
+//! realm, the startup banner, calendar product ids, the name mail clients see
+//! during setup) comes from here. That keeps the rebrand to a single file when
+//! merging upstream releases, instead of a scattering of string edits.
+//!
+//! These are macros, not constants, so they can be joined into other string
+//! literals at compile time with `concat!`.
+
+/// The product name: `INBUXA`.
+#[macro_export]
+macro_rules! brand {
+    () => {
+        "INBUXA"
+    };
+}
+
+/// The server's full name: `INBUXA Server`.
+#[macro_export]
+macro_rules! brand_server {
+    () => {
+        concat!($crate::brand!(), " Server")
+    };
+}
+
+/// The iCalendar and vCard `PRODID`.
+#[macro_export]
+macro_rules! brand_prodid {
+    () => {
+        concat!("-//", $crate::brand!(), "//", $crate::brand_server!(), "//EN")
+    };
+}

crates/types/src/lib.rs

@@ -6,6 +6,7 @@
 
 pub mod acl;
 pub mod blob;
+pub mod branding;
 pub mod blob_hash;
 pub mod collection;
 pub mod dead_property;