TypeError: cannot use 'tuple' as a dict key in LRUCache on Python 3.14

[baconisgood99-ship-it]

Environment:

• Python 3.14.5
• Jinja2 3.1.6
• Starlette/FastAPI (TemplateResponse)
• Windows 10
• Running as a PyInstaller bundled executable

Error:
TypeError: cannot use 'tuple' as a dict key (unhashable type: 'dict')

Traceback:
File "jinja2\environment.py", line 964, in _load_template
template = self.cache.get(cache_key)
File "jinja2\utils.py", line 477, in get
return self[key]
File "jinja2\utils.py", line 515, in getitem
rv = self._mapping[key]
TypeError: cannot use 'tuple' as a dict key (unhashable type: 'dict')

To reproduce:
Use Jinja2's TemplateResponse via Starlette on Python 3.14. The LRUCache
in jinja2/utils.py constructs a cache key that contains a dict under
Python 3.14, which is no longer hashable.

Workaround:
Setting env.cache = None on the Jinja2 Environment disables the cache
and prevents the error.

Notes:
This may be related to changes in how Python 3.14 handles tuple hashing
or dict construction internally. The cache_key generation in
environment.py may be producing a different type under 3.14 than expected.

Environment:

• Python version:
• Jinja version: