refactor(drivers): organize backup modules into drivers subfolder

- Move all backup_*.py files to libtisbackup/drivers/ subdirectory
- Move XenAPI.py and copy_vm_xcp.py to drivers/ (driver-specific)
- Create drivers/__init__.py with automatic driver imports
- Update tisbackup.py imports to use new structure
- Add pyvmomi>=8.0.0 as mandatory dependency
- Sync requirements.txt with pyproject.toml dependencies
- Add pylint>=3.0.0 and pytest-cov>=6.0.0 to dev dependencies
- Configure pylint and coverage tools in pyproject.toml
- Add conventional commits guidelines to CLAUDE.md
- Enhance .gitignore with comprehensive patterns for Python, IDEs, testing, and secrets
- Update CLAUDE.md documentation with new structure and tooling

Breaking Changes:
- Drivers must now be imported from libtisbackup.drivers instead of libtisbackup
- All backup driver files relocated to drivers/ subdirectory

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

libtisbackup/process.py

@@ -0,0 +1,97 @@
+#!/usr/bin/python3
+# -*- coding: utf-8 -*-
+# -----------------------------------------------------------------------
+#    This file is part of TISBackup
+#
+#    TISBackup is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    TISBackup is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with TISBackup.  If not, see <http://www.gnu.org/licenses/>.
+#
+# -----------------------------------------------------------------------
+
+"""Process execution and monitoring utilities."""
+
+import errno
+import os
+import select
+import subprocess
+
+
+def call_external_process(shell_string):
+    """Execute a shell command and raise exception on non-zero exit code."""
+    p = subprocess.call(shell_string, shell=True)
+    if p != 0:
+        raise Exception("shell program exited with error code " + str(p), shell_string)
+
+
+def monitor_stdout(aprocess, onoutputdata, context):
+    """Reads data from stdout and stderr from aprocess and return as a string
+    on each chunk, call a call back onoutputdata(dataread)
+    """
+    assert isinstance(aprocess, subprocess.Popen)
+    read_set = []
+    stdout = []
+    line = ""
+
+    if aprocess.stdout:
+        read_set.append(aprocess.stdout)
+    if aprocess.stderr:
+        read_set.append(aprocess.stderr)
+
+    while read_set:
+        try:
+            rlist, wlist, xlist = select.select(read_set, [], [])
+        except select.error as e:
+            if e.args[0] == errno.EINTR:
+                continue
+            raise
+
+        # Reads one line from stdout
+        if aprocess.stdout in rlist:
+            data = os.read(aprocess.stdout.fileno(), 1)
+            data = data.decode(errors="ignore")
+            if data == "":
+                aprocess.stdout.close()
+                read_set.remove(aprocess.stdout)
+            while data and data not in ("\n", "\r"):
+                line += data
+                data = os.read(aprocess.stdout.fileno(), 1)
+                data = data.decode(errors="ignore")
+            if line or data in ("\n", "\r"):
+                stdout.append(line)
+                if onoutputdata:
+                    onoutputdata(line, context)
+            line = ""
+
+        # Reads one line from stderr
+        if aprocess.stderr in rlist:
+            data = os.read(aprocess.stderr.fileno(), 1)
+            data = data.decode(errors="ignore")
+            if data == "":
+                aprocess.stderr.close()
+                read_set.remove(aprocess.stderr)
+            while data and data not in ("\n", "\r"):
+                line += data
+                data = os.read(aprocess.stderr.fileno(), 1)
+                data = data.decode(errors="ignore")
+            if line or data in ("\n", "\r"):
+                stdout.append(line)
+                if onoutputdata:
+                    onoutputdata(line, context)
+            line = ""
+
+    aprocess.wait()
+    if line:
+        stdout.append(line)
+        if onoutputdata:
+            onoutputdata(line, context)
+    return "\n".join(stdout)