Fix Python crash when hiding the title bar of more windows

[Valer100]

I found out why the crash in #59 was happening while experimenting with window procedures in a project of mine: it is because the code stores the window procedures (the old and the new ones) in the same variables, regardless of the window. When storing the second window's procedures, the procedures of the first one are lost and that's why the crash is happening. This PR addresses this issue by storing the window procedures in unique variables for every window. Fixes #59.

Summary by Sourcery

Ensure window procedure hooks are stored and restored per-window to prevent crashes when manipulating multiple windows.

Bug Fixes:

• Store old and new window procedures under hwnd-specific identifiers so each window maintains its own procedures.
• Restore the original window procedure using the hwnd-specific stored value when unhiding a window.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This PR fixes a crash when hiding the title bar on multiple windows by making the stored window procedure callbacks unique per window handle and updating the restore logic accordingly.

File-Level Changes

Change	Details	Files
Make stored window procedure callbacks unique per window to avoid overwriting between different windows.	Compute hwnd earlier via module_find(window) before defining the window procedure names. Derive old/new window procedure keys from the hwnd (e.g., old_wndproc_, new_wndproc_) instead of using shared global names. Keep the prototype definition unchanged but tied to the per-window procedure names.	hPyT/hPyT.py
Update unhide logic to restore the correct original window procedure for each window.	Look up old window procedure in globals() using the per-window key based on hwnd. Restore the window procedure from the per-window stored value and then clear only that specific entry.	hPyT/hPyT.py

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#59	Prevent Python from crashing when hiding the title bar on multiple windows (e.g., main Tk window and one or more Toplevels) by correctly handling per-window window procedures.	✅
#59	Ensure that restoring (unhiding) the title bar for any window correctly reinstalls that specific window’s original window procedure instead of a shared/global one.	✅

Possibly linked issues

• [BUG] Python crashes when trying to hide the titlebar of a Toplevel while the main window's titlebar is also hidden #59: PR fixes crash by storing unique window procedures per window, resolving the multi-window titlebar hiding crash in issue [BUG] Python crashes when trying to hide the titlebar of a Toplevel while the main window's titlebar is also hidden #59.
• [BUG] Python crashes when trying to hide the titlebar of a Toplevel while the main window's titlebar is also hidden #59: They describe the same crash; PR fixes it by storing old/new window procedures uniquely per window handle.

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[sourcery-ai]

Hey - I've found 1 issue, and left some high level feedback:

• Instead of dynamically creating per-window global names like old_wndproc_{hwnd}, consider keeping a dedicated dict keyed by hwnd (e.g. _wndprocs[hwnd] = {...}) to avoid polluting the global namespace and make lifecycle management clearer.
• When storing per-window procedures in globals keyed by hwnd, think about cleanup for windows that are never unhided (or that are destroyed) to avoid leaking entries if this code is used with many short-lived windows.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Instead of dynamically creating per-window global names like `old_wndproc_{hwnd}`, consider keeping a dedicated dict keyed by `hwnd` (e.g. `_wndprocs[hwnd] = {...}`) to avoid polluting the global namespace and make lifecycle management clearer.
- When storing per-window procedures in globals keyed by `hwnd`, think about cleanup for windows that are never `unhide`d (or that are destroyed) to avoid leaking entries if this code is used with many short-lived windows.

## Individual Comments

### Comment 1
<location> `hPyT/hPyT.py:209-211` </location>
<code_context>
-        if globals().get("old_wndproc") is not None:
-            set_window_long(hwnd, GWL_WNDPROC, globals()["old_wndproc"])
-            globals()["old_wndproc"] = None
+        if globals().get(f"old_wndproc_{hwnd}") is not None:
+            set_window_long(hwnd, GWL_WNDPROC, globals()[f"old_wndproc_{hwnd}"])
+            globals()[f"old_wndproc_{hwnd}"] = None

         # Restore the original height if no_span was used
</code_context>

<issue_to_address>
**issue (bug_risk):** `new_wndproc_*` entries are never cleared, which can leak per-window state.

In `unhide`, you reset `old_wndproc_{hwnd}` but leave any `new_wndproc_{hwnd}` entry in `globals()`. This leaves stale wndproc references for windows that are no longer hooked. When unhooking, please also clear or delete the corresponding `new_wndproc_{hwnd}` entry so per-window state is fully released.
</issue_to_address>

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[Zingzy]

Hi, @Valer100 nice work! Just a question, why cant we use dictionaries instead of dynamic vars?

[Valer100]

We can use dictionaries too, but I didn't think about it first, because I've seen that the procs were stored inside dynamically created global variables before. If you want, I can modify the code to store them in 2 separate dictionaries, one for the old ones and another one for the new ones.