Many `snprintf` truncation warnings

GCC `-Wformat-truncation=2` flag warns about potential truncations on the source content.

It flags many warnings in Loguru:

```
[108/305] Compiling C++ object src/libs/loguru/libloguru.a.p/loguru.cpp.o
../../src/libs/loguru/loguru.cpp: In function ‘void loguru::print_preamble_header(char*, size_t)’:
../../src/libs/loguru/loguru.cpp:1259:85: warning: ‘time ’ directive output truncated writing 13 bytes into a region of size 1 [-Wformat-truncation=]
1259 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "time ");
| ~^~~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin_snprintf’ output 14 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1265:85: warning: ‘( uptime ) ’ directive output truncated writing 12 bytes into a region of size 1 [-Wformat-truncation=]
1265 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "( uptime ) ");
| ~^~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin_snprintf’ output 13 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1271:85: warning: ‘%-*s’ directive output truncated writing 16 bytes into a region of size 0 [-Wformat-truncation=]
1271 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "[%-*s]", LOGURU_THREADNAME_WIDTH, " thread name/id");
| ^~~~ ~~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output 19 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1277:84: warning: ‘%*s’ directive output truncated writing 23 bytes into a region of size 1 [-Wformat-truncation=]
1277 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "%*s:line ", LOGURU_FILENAME_WIDTH, "file");
| ^~~ ~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output 31 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1283:85: warning: ‘ v’ directive output truncated writing 4 bytes into a region of size 1 [-Wformat-truncation=]
1283 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, " v");
| ~^~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin_snprintf’ output 5 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1289:79: warning: ‘| ’ directive output truncated writing 2 bytes into a region of size 1 [-Wformat-truncation=]
1289 | (void)snprintf(out_buff + pos, out_buff_size - pos, "| ");
| ~^
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin_snprintf’ output 3 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp: In function ‘void loguru::get_thread_name(char*, long long unsigned int, bool)’:
../../src/libs/loguru/loguru.cpp:1068:82: warning: ‘__builtin_snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
1068 | snprintf(buffer, static_cast(length), "%s", name);
| ^
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin_snprintf’ output 1 or more bytes (assuming 2) into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1107:80: warning: ‘%X’ directive output may be truncated writing between 1 and 8 bytes into a region of size 1 [-Wformat-truncation=]
1107 | snprintf(buffer, static_cast(length), "%X", static_cast(thread_id));
| ^~
../../src/libs/loguru/loguru.cpp:1107:79: note: using the range [0, 4294967295] for directive argument
1107 | snprintf(buffer, static_cast(length), "%X", static_cast(thread_id));
| ^~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 2 and 9 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1105:80: warning: ‘%*X’ directive output may be truncated writing between 1 and 2147483648 bytes into a region of size 1 [-Wformat-truncation=]
1105 | snprintf(buffer, static_cast(length), "%*X", static_cast(length - 1), static_cast(thread_id));
| ^~~
../../src/libs/loguru/loguru.cpp:1105:79: note: assuming directive output of 9 bytes
1105 | snprintf(buffer, static_cast(length), "%*X", static_cast(length - 1), static_cast(thread_id));
| ^~~~~
../../src/libs/loguru/loguru.cpp:1105:79: note: using the range [0, 4294967295] for directive argument
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 2 and 2147483649 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp: In function ‘void loguru::print_preamble(char*, size_t, loguru::Verbosity, const char*, unsigned int)’:
../../src/libs/loguru/loguru.cpp:1325:71: warning: ‘% 4d’ directive output may be truncated writing between 4 and 11 bytes into a region of size 5 [-Wformat-truncation=]
1325 | snprintf(level_buff, sizeof(level_buff) - 1, "% 4d", verbosity);
| ^~~~
../../src/libs/loguru/loguru.cpp:1325:70: note: directive argument in the range [1, 2147483647]
1325 | snprintf(level_buff, sizeof(level_buff) - 1, "% 4d", verbosity);
| ^~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 5 and 12 bytes into a destination of size 5
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1338:84: warning: ‘%02d’ directive output truncated writing between 2 and 11 bytes into a region of size 1 [-Wformat-truncation=]
1338 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "%02d:%02d:%02d.%03lld ",
| ^~~~
../../src/libs/loguru/loguru.cpp:1338:83: note: directive argument in the range [-999, 999]
1338 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "%02d:%02d:%02d.%03lld ",
| ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 14 and 42 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1345:85: warning: ‘%8.3f’ directive output truncated writing between 8 and 314 bytes into a region of size 0 [-Wformat-truncation=]
1345 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "(%8.3fs) ",
| ^~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 13 and 319 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1352:85: warning: ‘%-*s’ directive output truncated writing 16 or more bytes into a region of size 0 [-Wformat-truncation=]
1352 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "[%-*s]",
| ^~~~
1353 | LOGURU_THREADNAME_WIDTH, thread_name);
| ~~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output 19 or more bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1361:84: warning: ‘%*s’ directive output truncated writing 23 bytes into a region of size 1 [-Wformat-truncation=]
1361 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "%*s:%-5u ",
| ^~~
1362 | LOGURU_FILENAME_WIDTH, shortened_filename, line);
| ~~~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 31 and 36 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1368:84: warning: ‘%4s’ directive output truncated writing between 4 and 5 bytes into a region of size 1 [-Wformat-truncation=]
1368 | int bytes = snprintf(out_buff + pos, out_buff_size - pos, "%4s",
| ^~~
1369 | level_buff);
| ~~~~~~~~~~
In file included from /usr/include/stdio.h:866,
from /usr/include/c++/11/cstdio:42,
from ../../src/libs/loguru/loguru.cpp:38:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:71:35: note: ‘__builtin___snprintf_chk’ output between 5 and 6 bytes into a destination of size 1
71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
| ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
72 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
73 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
../../src/libs/loguru/loguru.cpp:1375:79: warning: ‘| ’ directive output truncated writing 2 bytes into a region of size 1 [-Wformat-truncation=]
1375 | (void)snprintf(out_buff + pos, out_buff_size - pos, "| ");
```

Start in src/libs/loguru/loguru.cpp at get_thread_name, print_preamble_header, and print_preamble, where the reported snprintf warnings occur. Reproduce the build with GCC -Wformat-truncation=2, inspect the affected buffer sizes and formatting calls, and confirm that the warnings are removed without changing log output.

Written by the indexing model from the issue text.