webapp: extract service layer (config.py + services/) from app.py

Phase 1a of a multi-session refactor toward a clean blueprint
structure. Pulls the helper code that lived alongside the routes in
the 1621-line app.py into focused modules. app.py is now 625 lines
of mostly routes plus a small Flask wiring header. Behaviour is
unchanged: smoke-tested against the 8 main GET routes (200 OK).

New modules:

- config.py            env vars + IMAGE_TYPES + FRIENDLY_NAMES +
                       SHARED_DEPLOY_* taxonomy + unattend XML
                       namespaces.
- services/audit.py    audit log file handler + audit() helper.
- services/csrf.py     session CSRF token + before_request validator
                       wired via init_csrf(app).
- services/fs.py       image_root / deploy_path / unattend_path /
                       control_path / tools_path + load_json /
                       save_json + resolve_destination.
- services/system.py   service_status / find_usb_mounts /
                       find_upload_sources.
- services/images.py   image_status + load_image_config.
- services/deploy.py   import_deploy + _merge_tree +
                       _replace_with_symlink + allowed_import_source.
- services/unattend.py parse_unattend / build_unattend_xml /
                       extract_form_data and the qn / qwcm / settings
                       pass helpers.
- services/wim.py      extract_startnet / update_startnet / list_files
                       wrapping wimextract / wimupdate / wimdir.

Endpoint names kept stable (dashboard, clonezilla_backups, etc.) so
existing url_for(...) calls in templates are unchanged. Phase 1b
(Flask blueprints with ".endpoint" naming) deferred to a future
session because it requires updating ~30 url_for sites in templates
and is mostly cosmetic.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

webapp/services/deploy.py

@@ -0,0 +1,96 @@
+"""Image deploy import logic: copy/move from a USB or upload-dir source
+into ``SAMBA_SHARE/<image_type>/Deploy/`` while merging shared subdirs
+(``Out-of-box Drivers`` etc.) into ``SAMBA_SHARE/_shared/`` and replacing
+the per-image copies with symlinks. This is what lets two image types
+re-use the same multi-GB driver tree without doubling disk usage.
+"""
+
+import os
+import shutil
+
+import config
+from services.system import find_usb_mounts
+
+
+def _replace_with_symlink(link_path, target_path):
+    """Replace a file/dir/symlink at link_path with a symlink to target_path."""
+    if os.path.islink(link_path):
+        os.remove(link_path)
+    elif os.path.isdir(link_path):
+        shutil.rmtree(link_path)
+    os.symlink(target_path, link_path)
+
+
+def _merge_tree(src, dst, move=False):
+    """Recursively merge src tree into dst, overwriting existing files.
+
+    When move=True, files are moved instead of copied (saves disk space
+    on imports from the local upload-dir).
+    """
+    _transfer = shutil.move if move else shutil.copy2
+    _transfer_tree = shutil.move if move else shutil.copytree
+    for item in os.listdir(src):
+        s = os.path.join(src, item)
+        d = os.path.join(dst, item)
+        if os.path.isdir(s):
+            if os.path.isdir(d):
+                _merge_tree(s, d, move=move)
+            else:
+                if os.path.exists(d):
+                    os.remove(d)
+                _transfer_tree(s, d)
+        else:
+            os.makedirs(os.path.dirname(d), exist_ok=True)
+            _transfer(s, d)
+
+
+def import_deploy(src_deploy, dst_deploy, target="", move=False):
+    """Import Deploy/ contents, redirecting shared subdirs into _shared/."""
+    scoped_shared = []
+    prefix_key = ""
+    for prefix, dirs in config.SHARED_DEPLOY_SCOPED.items():
+        if target.startswith(prefix):
+            scoped_shared = dirs
+            prefix_key = prefix
+            break
+
+    _transfer = shutil.move if move else shutil.copy2
+    _transfer_tree = shutil.move if move else shutil.copytree
+
+    os.makedirs(dst_deploy, exist_ok=True)
+    for item in os.listdir(src_deploy):
+        src_item = os.path.join(src_deploy, item)
+        dst_item = os.path.join(dst_deploy, item)
+
+        if not os.path.isdir(src_item):
+            _transfer(src_item, dst_item)
+            continue
+
+        if item in config.SHARED_DEPLOY_GLOBAL:
+            shared_dest = os.path.join(config.SHARED_DIR, item)
+            os.makedirs(shared_dest, exist_ok=True)
+            _merge_tree(src_item, shared_dest, move=move)
+            _replace_with_symlink(dst_item, shared_dest)
+            continue
+
+        if item in scoped_shared:
+            shared_dest = os.path.join(config.SHARED_DIR, f"{prefix_key}{item}")
+            os.makedirs(shared_dest, exist_ok=True)
+            _merge_tree(src_item, shared_dest, move=move)
+            _replace_with_symlink(dst_item, shared_dest)
+            continue
+
+        if os.path.isdir(dst_item):
+            _merge_tree(src_item, dst_item, move=move)
+        else:
+            _transfer_tree(src_item, dst_item)
+
+
+def allowed_import_source(source):
+    """True if source is a USB mount or under the upload dir."""
+    usb = find_usb_mounts()
+    if any(source == m or source.startswith(m + "/") for m in usb):
+        return True
+    if source == config.UPLOAD_DIR or source.startswith(config.UPLOAD_DIR + "/"):
+        return os.path.isdir(source)
+    return False