feat(cli): improve file discovery and completion

- Render remote files as an aligned table with JSON and TSV alternatives.
- Add Bash and Zsh completion for commands, options, paths, and remote files.
- Allow downloads by exact filename while rejecting ambiguous duplicate names.
- Cover table formatting, completion scripts, and selector resolution with tests.

tests/test_nanoshare_cli.py

@@ -8,6 +8,8 @@ sys.path.insert(0, str(Path(__file__).resolve().parents[1] / 'cli'))
 
 from nanoshare_client import cli
 from nanoshare_client.auth import _CallbackServer
+from nanoshare_client.completion import script as completion_script
+from nanoshare_client.table import format_table
 
 class FakeClient:
   def __init__(self):
@@ -55,6 +57,53 @@ def test_sync_uploads_new_local_file_and_writes_state(tmp_path, monkeypatch):
   state = json.loads((tmp_path / '.nanoshare-sync' / 'state.json').read_text())
   assert state['files']['hello.txt']['file_id'] == 'file_1'
 
+def test_completion_scripts_include_commands():
+  zsh = completion_script('zsh')
+  bash = completion_script('bash')
+
+  assert 'compdef _nanoshare nanoshare' in zsh
+  assert 'complete -F _nanoshare nanoshare' in bash
+  assert 'login upload list download sync watch completion' in zsh
+  assert 'login upload list download sync watch completion' in bash
+
+def test_resolve_remote_file_accepts_id_or_exact_name():
+  files = [
+    {'file_id': 'file_1', 'file_name': 'report.pdf'},
+    {'file_id': 'file_2', 'file_name': 'photo.png'},
+  ]
+
+  assert cli._resolve_remote_file(files, 'file_1')['file_name'] == 'report.pdf'
+  assert cli._resolve_remote_file(files, 'photo.png')['file_id'] == 'file_2'
+
+def test_resolve_remote_file_rejects_duplicate_names():
+  files = [
+    {'file_id': 'file_1', 'file_name': 'report.pdf'},
+    {'file_id': 'file_2', 'file_name': 'report.pdf'},
+  ]
+
+  try:
+    cli._resolve_remote_file(files, 'report.pdf')
+  except RuntimeError as exc:
+    assert 'multiple remote files' in str(exc)
+  else:
+    raise AssertionError('expected duplicate names to raise')
+
+def test_format_table_aligns_columns():
+  output = format_table(
+    ['ID', 'Name', 'Size'],
+    [
+      ['abc', 'short.txt', '1 KB'],
+      ['longer-id', 'a much longer file name.png', '22 MB'],
+    ],
+  )
+
+  assert output.splitlines() == [
+    'ID         Name                         Size',
+    '---------  ---------------------------  -----',
+    'abc        short.txt                    1 KB',
+    'longer-id  a much longer file name.png  22 MB',
+  ]
+
 def test_login_callback_returns_without_waiting_for_timeout():
   server = _CallbackServer('127.0.0.1', 0, 'expected-state')
   result = {}