refactor(ext/node): rewrite process stdio to match Node.js pattern

[bartlomieju]

Summary

Rewrites process.stdin/stdout/stderr creation to exactly match Node.js's
lib/internal/bootstrap/switches/is_main_thread.js pattern. This is a
follow-up / alternative approach to #33154.

Key changes:

• process.stdout/stderr are now created based on guessHandleType(fd):
  • TTY → tty.WriteStream(fd) (libuv TTY handle via net.Socket)
  • PIPE/TCP → net.Socket({ fd }) (libuv Pipe/TCP handle)
  • FILE → SyncWriteStream(fd) (synchronous fs.writeSync)
  • UNKNOWN → dummy Writable
• process.stdin similarly uses the correct Node.js stream type per fd type
• Removes the old pattern of wrapping Deno.stdout.writeSync() in a generic
  Writable regardless of fd type
• Simplifies the bootstrap code — removes separate TTY vs non-TTY branching
  and warmup stream replacement logic
• Deno.stdin/stdout/stderr continue to work via RID-based ops; a
  __setNodeStreams() hook is added for future delegation

Bug fixes included:

• child_process: #_waitForChildStreamsToClose now skips resume() on
  parent process stdout/stderr to prevent EBADF when they are write-only
  net.Socket instances
• isTTY is now undefined for non-TTY streams (matching Node.js) instead
  of false

Fixes #33131: The old code used io.stdout.isTerminal() (Rust's
is_terminal()) to decide whether to create a tty.WriteStream. On Windows
Git Bash, Rust's is_terminal() returns true but uv_tty_init fails with
EBADF because Git Bash uses named pipes, not a real Windows console. This PR
switches to guessHandleType(fd) (which calls libuv's uv_guess_handle),
matching Node.js. On Git Bash, uv_guess_handle correctly returns PIPE, so
a net.Socket is created instead of attempting TTY initialization.

Net deletions: ~200 lines removed.

Closes #33131

Test plan

• ./x test-node process_test — all pass (82 passed, 0 failed)
• ./x test-node child_process_test — all pass (47 passed, 0 failed)
• ./x test-spec pipe_open_fd — 5/5 pass
• ./x test-spec net_socket_fd — 4/4 pass
• ./x test-spec stdio — 3/3 pass
• ./x test-spec tty — 3/3 pass
• ./x test-spec process — all pass (only pre-existing denort failures)
• ./x test-spec node — 246 tests, only pre-existing denort/compile failures
• ./x test-unit process_test — pass
• ./x test-unit stdio_test — pass
• Manual: process.stdout.destroy() + subsequent write still works (indestructible)
• Manual: piped stdout correctly creates net.Socket, file redirect creates SyncWriteStream

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