feat!: adopt Python 3.14 and 3.15 language features

- Require Python 3.15 for the server and Python 3.14 for the CLI.
- Match the server requirement to quart_common's Python 3.15 features.
- Replace future annotations with native deferred evaluation.
- Defer CLI command dependencies and QR imports on Python 3.15.
- Enable argparse suggestions for mistyped CLI commands.
- Remove the obsolete tomllib import fallback.
- Update my_helpers and quart_common submodule references.
- Lock test dependencies and exclude them from Docker installations.
- Add regression coverage for lazy imports and deferred annotations.
- Document runtime requirements and standalone CLI validation.
- Validate 276 tests on Python 3.15 and 18 CLI tests on Python 3.14.

BREAKING CHANGE: The server now requires Python 3.15+ and the standalone CLI requires Python 3.14+.

routes/api/cli_auth.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 import secrets
 from urllib.parse import urlencode
 

routes/api/download.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 from my_modules.app.setup import LIMITER
 from my_modules.decoratory.header import token_required
 from quart_common.web.wide_event import add_wide_event_context

routes/api/events.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 import asyncio
 import json
 

routes/api/link.py

@@ -7,8 +7,6 @@ UI and /api routes.
 Every call needs a bearer token carrying the `files` or `mesh` scope; the endpoint is rate
 limited and body-size capped. Keep /rpc on the internal node network.
 '''
-from __future__ import annotations
-
 import base64
 import os
 

routes/side/link_composer.py

@@ -1,5 +1,3 @@
-from __future__ import annotations
-
 from urllib.parse import quote, unquote, urlparse
 
 from quart import Blueprint, Response, abort, jsonify, render_template, request, session, url_for