fix: eliminate shell noise from terminal output with fence markers

- Wrap commands with unique fence markers (printf FENCE; cmd; printf FENCE)
  to isolate real output from shell init/exit noise (oh-my-zsh, macOS
  session restore/save, docker plugin errors, etc.)
- Expand _clean_shell_noise to cover zsh/macOS patterns and strip from
  both beginning and end (fallback when fences are missing)
- Fix BSD find compatibility: fallback to simple find when -printf
  produces empty output (macOS)
- Fix test_terminal_disk_usage: use sys.modules to get the real module
  instead of the shadowed function from tools/__init__.py
- Add 13 new unit tests for fence extraction and zsh noise patterns

tests/tools/test_file_tools_live.py

@@ -17,7 +17,13 @@ import pytest
 
 sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
 
-from tools.environments.local import LocalEnvironment, _clean_shell_noise, _SHELL_NOISE_SUBSTRINGS
+from tools.environments.local import (
+    LocalEnvironment,
+    _clean_shell_noise,
+    _extract_fenced_output,
+    _OUTPUT_FENCE,
+    _SHELL_NOISE_SUBSTRINGS,
+)
 from tools.file_operations import ShellFileOperations
 
 
@@ -28,6 +34,7 @@ from tools.file_operations import ShellFileOperations
 _ALL_NOISE_PATTERNS = list(_SHELL_NOISE_SUBSTRINGS) + [
     "bash: ",
     "Inappropriate ioctl",
+    "Auto-suggestions:",
 ]
 
 
@@ -125,11 +132,84 @@ class TestCleanShellNoise:
         _assert_clean(result)
 
     def test_noise_in_middle_not_stripped(self):
-        """Only LEADING noise is stripped -- noise in the middle is real output."""
+        """Noise in the middle is real output and should be preserved."""
         output = "real\nbash: no job control in this shell\nmore real\n"
         result = _clean_shell_noise(output)
         assert result == output
 
+    def test_zsh_restored_session(self):
+        output = "Restored session: Mon Mar  2 22:16:54 +03 2026\nhello\n"
+        result = _clean_shell_noise(output)
+        assert result == "hello\n"
+
+    def test_zsh_saving_session_trailing(self):
+        output = "hello\nSaving session...completed.\n"
+        result = _clean_shell_noise(output)
+        assert result == "hello\n"
+
+    def test_zsh_oh_my_zsh_banner(self):
+        output = "Oh My Zsh on! | Auto-suggestions: press right\nhello\n"
+        result = _clean_shell_noise(output)
+        assert result == "hello\n"
+
+    def test_zsh_full_noise_sandwich(self):
+        """Both leading and trailing zsh noise stripped."""
+        output = (
+            "Restored session: Mon Mar  2\n"
+            "command not found: docker\n"
+            "Oh My Zsh on!\n"
+            "actual output\n"
+            "Saving session...completed.\n"
+        )
+        result = _clean_shell_noise(output)
+        assert result == "actual output\n"
+
+    def test_last_login_stripped(self):
+        output = "Last login: Mon Mar 2 22:00:00 on ttys001\nhello\n"
+        result = _clean_shell_noise(output)
+        assert result == "hello\n"
+
+
+# ── _extract_fenced_output unit tests ────────────────────────────────────
+
+class TestExtractFencedOutput:
+    def test_normal_fenced_output(self):
+        raw = f"noise\n{_OUTPUT_FENCE}hello world\n{_OUTPUT_FENCE}more noise\n"
+        assert _extract_fenced_output(raw) == "hello world\n"
+
+    def test_no_trailing_newline(self):
+        """printf output with no trailing newline is preserved."""
+        raw = f"noise{_OUTPUT_FENCE}exact{_OUTPUT_FENCE}noise"
+        assert _extract_fenced_output(raw) == "exact"
+
+    def test_no_fences_falls_back(self):
+        """Without fences, falls back to pattern-based cleaning."""
+        raw = "bash: no job control in this shell\nhello\n"
+        result = _extract_fenced_output(raw)
+        assert result == "hello\n"
+
+    def test_only_start_fence(self):
+        """Only start fence (e.g. user command called exit)."""
+        raw = f"noise{_OUTPUT_FENCE}hello\nSaving session...\n"
+        result = _extract_fenced_output(raw)
+        assert result == "hello\n"
+
+    def test_user_outputs_fence_string(self):
+        """If user command outputs the fence marker, it is preserved."""
+        raw = f"noise{_OUTPUT_FENCE}{_OUTPUT_FENCE}real\n{_OUTPUT_FENCE}noise"
+        result = _extract_fenced_output(raw)
+        # first fence -> last fence captures the middle including user's fence
+        assert _OUTPUT_FENCE in result
+        assert "real\n" in result
+
+    def test_empty_command_output(self):
+        raw = f"noise{_OUTPUT_FENCE}{_OUTPUT_FENCE}noise"
+        assert _extract_fenced_output(raw) == ""
+
+    def test_multiline_output(self):
+        raw = f"noise\n{_OUTPUT_FENCE}line1\nline2\nline3\n{_OUTPUT_FENCE}noise\n"
+        assert _extract_fenced_output(raw) == "line1\nline2\nline3\n"
+
 
 # ── LocalEnvironment.execute() ───────────────────────────────────────────