Rename to inbuxa-migrate

The crate, binary, library path and every name the tool writes or reads
become inbuxa-migrate: the CLI name and about text, the HTTP user agent,
the credential variables (INBUXA_MIGRATE_PASSWORD, _TOKEN,
_EWS_CLIENT_SECRET and _GRAPH_TOKEN, with no fallback to the old names),
thread names, synthesized UIDs and calendar addresses
(urn:x-inbuxa-migrate:attendee:), and the Maildir file suffix used by the
export script. This is a new tool, so archives written by Vandelay are not
read back.

The version moves to the date scheme the release tags use (2026.9.30), and
the package metadata points at the inbuxa-migrate repository. The cargo-dist
and MSI metadata goes with the release tooling it served.

Modified files carry an added copyright line; the original notices stay.

tests/integration_webdav.rs

@@ -1,5 +1,6 @@
 /*
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ * SPDX-FileCopyrightText: 2026 John Coffey <[email protected]>
  *
  * SPDX-License-Identifier: Apache-2.0 OR MIT
  */
@@ -15,9 +16,9 @@ use integration::validate::{
 use integration::webdav::{AccountSeed, WebDav};
 use integration::{Account, Endpoint};
 
-use vandelay::error::Error;
-use vandelay::sync::import_dav;
-use vandelay::sync::import_dav::{DavAuth, DavImportConfig, DavKindArg};
+use inbuxa_migrate::error::Error;
+use inbuxa_migrate::sync::import_dav;
+use inbuxa_migrate::sync::import_dav::{DavAuth, DavImportConfig, DavKindArg};
 
 fn webdav_config(account: &Account, http: &Endpoint) -> DavImportConfig {
     DavImportConfig {
@@ -319,7 +320,7 @@ fn webdav_starts_seeds_and_imports() {
         drop(conn);
 
         let new_payload = format!(
-            "added-{} content for vandelay webdav add-after-import probe\n",
+            "added-{} content for inbuxa-migrate webdav add-after-import probe\n",
             seed.username
         );
         let new_payload_bytes = new_payload.as_bytes().to_vec();