Sim posix fixes

[LingaoM]

Summary

This PR improves NuttX sim compatibility for standard POSIX-facing APIs used by simulated applications.

Changes included:

• Add AF_LOCAL / AF_UNIX support to sim usrsock, so applications can use the normal NuttX socket API to communicate with host Unix-domain sockets.
• Translate hostfs POSIX byte-range lock operations. fcntl(F_GETLK/F_SETLK) reaches file systems as FIOC_* ioctl commands after VFS handling; hostfs now converts those lock
  requests back to host fcntl() for host-backed files.
• Add built-in http and https service entries to libc netdb so getservbyname() / getaddrinfo() can resolve common service names without requiring numeric ports.

The changes keep applications using standard NuttX/POSIX interfaces rather than exposing host-only APIs directly to application code.

Impact

• Affects sim builds using usrsock, hostfs, or libc netdb.
• Applications can use socket(AF_LOCAL, ...) through the normal NuttX socket layer on sim.
• Applications using hostfs can use non-blocking POSIX file locks through fcntl(F_GETLK/F_SETLK).
• F_SETLKW is intentionally left unsupported for hostfs and returns -ENOSYS, because forwarding a blocking host fcntl() could block the whole sim OS.
• http and https become available in the built-in service database when CONFIG_LIBC_NETDB=y.
• No hardware targets are affected by the sim host-side changes.

Testing

Host machine:

• Ubuntu 22.04 x86_64

Board/config:

• sim:nsh

Build test:

make clean
make -j16

Runtime tests performed with temporary hello examples, then restored before commit.

AF_LOCAL / usrsock test:

- Built sim:nsh with usrsock enabled.
- Ran a temporary hello app that connected to host Unix-domain sockets using normal NuttX socket(AF_LOCAL, ...).
- Verified both SOCK_STREAM and SOCK_SEQPACKET.
- The app exchanged data with a host socket server and printed:

AF_LOCAL usrsock test passed

hostfs file lock test:

- Built sim:nsh with:

CONFIG_FS_HOSTFS=y
CONFIG_SIM_HOSTFS=y
CONFIG_EXAMPLES_HELLO=y

- Ran a temporary hello app that mounted /tmp through hostfs, opened a host-backed file, then verified:

fcntl(fd, F_SETLK, ...)
fcntl(fd, F_GETLK, ...)
fcntl(fd, F_SETLK, F_UNLCK)

- The app printed:

hostfs fcntl lock test passed

netdb service-name test:

- Built sim:nsh with:

CONFIG_LIBC_NETDB=y
CONFIG_EXAMPLES_HELLO=y

- Ran a temporary hello app that verified:

getservbyname("http", "tcp")  -> port 80
getservbyname("https", "tcp") -> port 443

- The app printed:

getservbyname http/https test passed

[github-actions]

MemBrowse Memory Report

qemu-armv8a

• Code: .text.hostfs_ioctl +60 B (+0.0%, 315,466 B)
  No memory changes detected for:
• arduino-mega2560
• esp32-devkitc
• hifive1-revb
• mirtoo
• qemu-intel64
• rx65n-rsk2mb
• s698pm-dkit
• stm32-nucleo-f103rb