Initial build: Asterisk voicemail transcription + portal

- mailcmd replacement (vm_mailcmd.py): faster-whisper transcription (CPU int8),
  extractive summary + intent tags + spoken-digit number extraction,
  multipart/alternative HTML email, fail-safe relay of original message
- Telegram DM delivery (vm_telegram.py) with per-mailbox routing
- Caller-ID -> name (vm_contacts.py): file / google / carddav backends
- SQLite store (vm_store.py) with content-addressed audio
- FastAPI portal (vm_web.py): PIN login, list/play/delete, per-user settings,
  zero JS, loopback-only behind Apache TLS
- Backfill importer (vm_import.py) for existing spool recordings
- systemd unit, Apache vhost + certbot TLS, install.sh
- Docs: INSTALL, CONFIGURATION, ARCHITECTURE, OPERATIONS, SECURITY, TESTING

Verified end-to-end on mail.txt3.net: 157 historical messages backfilled,
live voicemail -> transcribed -> stored -> visible at https://vm.txt3.net.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 jp
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.