refactor: Replace unsafe strcpy with safer alternatives and fix build warnings

[iphydf]

Replaces unsafe strcpy calls with snprintf, memcpy, or strdup to mitigate potential buffer overflows. Also fixed -Wdouble-promotion build warnings in netprof.c and prompt.c by using explicit double casts and sprintf in configdir.c.

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This change is 

[JFreegman]

@JFreegman made 2 comments.
Reviewable status: 1 change requests, 0 of 1 approvals obtained (waiting on @iphydf).

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src/misc_tools.c line 491 at r2 (raw file):

on_error:
    snprintf(buf, TOXIC_MAX_NAME_LENGTH + 1, "%s", UNKNOWN_NAME);

The buffer size here (and in all the ones below) is TOX_MAX_NAME_LENGTH which is incidentally <= than TOXIC_MAX_NAME_LENGTH. Maybe we should pass the buffer size so there's less room for error.

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src/misc_tools.c line 694 at r2 (raw file):

    if (len > MAX_WINDOW_NAME_LENGTH) {
        snprintf(&cpy[MAX_WINDOW_NAME_LENGTH - 3], 4, "...");

Why 4 instead of sizeof(cpy)?

[iphydf]

@iphydf made 2 comments.
Reviewable status: 1 change requests, 0 of 1 approvals obtained (waiting on @JFreegman).

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src/misc_tools.c line 491 at r2 (raw file):

Previously, JFreegman wrote…

The buffer size here (and in all the ones below) is TOX_MAX_NAME_LENGTH which is incidentally <= than TOXIC_MAX_NAME_LENGTH. Maybe we should pass the buffer size so there's less room for error.

Done.

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src/misc_tools.c line 694 at r2 (raw file):

Previously, JFreegman wrote…

Why 4 instead of sizeof(cpy)?

Done.

[JFreegman]

@JFreegman reviewed 16 files and all commit messages, and resolved 2 discussions.
Reviewable status: complete! 1 of 1 approvals obtained.