Remove the internal fd table (fd_entry_t, is_fd_valid, fd_allows_read/write,
ESP_STDIO_BASIC_MODE tracking) from the console VFS.
Instead, console_open forwards directly to the primary backend's open_p,
so each open("/dev/console") creates a real fd in the underlying driver.
Read/write/fstat/fcntl/fsync all operate on the per-open fd from the
primary, not a stored init-time fd.
Structure:
- s_primary: separate variable for the primary backend entry
- s_auxiliary[]: slot-based array for auxiliary sinks (NULL = free)
- Scans all slots (no count variable) with NULL guards
- Auxiliaries opened lazily on first console open
- Closed when last console fd is closed (refcounted via s_open_count)
- Write and fsync fan-out protected by s_lock
Map logical /dev/console fds to the primary sink fd for select.
This avoids probing UART1/UART2 for stdout/stderr and keeps UART select state consistent.
Add stdio regression checks for logical fd mapping and symmetric uart_end_select teardown.
- Move the linux repl chip and deprecate chip related functions
- Update location of driver specific default config
- Add missing comments on the newly added functions in the affected components.
esp_stdio contains everything the old esp_vfs_console contained (the vfs stdio glue layer)
as well as other functionality related to stdio (previously referred to as console)
