[build] modernize build-frontend: python setup.py develop/install -> [uv ]pip install --no-build-isolation [-e ]. (#156027)

Modernize the development installation:

```bash
# python setup.py develop
python -m pip install --no-build-isolation -e .

# python setup.py install
python -m pip install --no-build-isolation .
```

Now, the `python setup.py develop` is a wrapper around `python -m pip install -e .` since `setuptools>=80.0`:

- pypa/setuptools#4955

`python setup.py install` is deprecated and will emit a warning during run. The warning will become an error on October 31, 2025.

- 9c4d383631/setuptools/command/install.py (L58-L67)

> ```python
> SetuptoolsDeprecationWarning.emit(
>     "setup.py install is deprecated.",
>     """
>     Please avoid running ``setup.py`` directly.
>     Instead, use pypa/build, pypa/installer or other
>     standards-based tools.
>     """,
>     see_url="https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html",
>     due_date=(2025, 10, 31),
> )
> ```

- pypa/setuptools#3849

Additional Resource:

- [Why you shouldn't invoke setup.py directly](https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/156027
Approved by: https://github.com/ezyang

setup.py

@@ -263,6 +263,7 @@ import json
 import shutil
 import subprocess
 import sysconfig
+import textwrap
 import time
 from collections import defaultdict
 from pathlib import Path
@@ -601,7 +602,7 @@ def build_deps() -> None:
         report(
             'Finished running cmake. Run "ccmake build" or '
             '"cmake-gui build" to adjust build options and '
-            '"python setup.py install" to build.'
+            '"python -m pip install --no-build-isolation -v ." to build.'
         )
         sys.exit()
 
@@ -1207,24 +1208,25 @@ def configure_extension_build() -> tuple[
 
 # post run, warnings, printed at the end to make them more visible
 build_update_message = """
-    It is no longer necessary to use the 'build' or 'rebuild' targets
+It is no longer necessary to use the 'build' or 'rebuild' targets
 
-    To install:
-      $ python setup.py install
-    To develop locally:
-      $ python setup.py develop
-    To force cmake to re-generate native build files (off by default):
-      $ CMAKE_FRESH=1 python setup.py develop
-"""
+To install:
+  $ python -m pip install --no-build-isolation -v .
+To develop locally:
+  $ python -m pip install --no-build-isolation -v -e .
+To force cmake to re-generate native build files (off by default):
+  $ CMAKE_FRESH=1 python -m pip install --no-build-isolation -v -e .
+""".strip()
 
 
 def print_box(msg: str) -> None:
-    lines = msg.split("\n")
-    size = max(len(l) + 1 for l in lines)
-    print("-" * (size + 2))
-    for l in lines:
-        print("|{}{}|".format(l, " " * (size - len(l))))
-    print("-" * (size + 2))
+    msg = textwrap.dedent(msg).strip()
+    lines = ["", *msg.split("\n"), ""]
+    max_width = max(len(l) for l in lines)
+    print("+" + "-" * (max_width + 4) + "+", file=sys.stderr, flush=True)
+    for line in lines:
+        print(f"|  {line:<{max_width}s}  |", file=sys.stderr, flush=True)
+    print("+" + "-" * (max_width + 4) + "+", file=sys.stderr, flush=True)
 
 
 def main() -> None: