refactor: rename the application package to docsgpt

The backend import package is now docsgpt, the name it will carry on PyPI;
application was far too generic to install into anyone's site-packages.
git mv plus a mechanical rewrite of every import, dotted string and path
reference: 734 Python files, the compose files, Dockerfile, workflows, docs,
setup scripts, devcontainer, k8s manifests, vscode config, pytest and coverage
config, .gitignore. Behaviour is unchanged.

Kept for one release:
- A top-level application package whose meta-path finder resolves
  application.x.y to the already-imported docsgpt.x.y object, so old imports
  and entry points (celery -A application.app.celery,
  uvicorn application.asgi:asgi_app) keep working with a FutureWarning.
- Celery registers every application.* task name as an alias of its
  docsgpt.* task on start-up, so messages queued by the previous release still
  run. The redbeat key prefix moves to redbeat:docsgpt:v2: so schedule entries
  the previous release wrote are left unread instead of firing twice.

The backend image builds from the repository root (docker build -f
docsgpt/Dockerfile .) so it can ship the alias package; a root .dockerignore
allow-lists docsgpt/ and application/ and keeps caches, local data, .env
files, the sample index files and the Dockerfile out. Compose and the image
workflows point at the new context.

docsgpt/agents/tools/tool_manager.py

@@ -0,0 +1,77 @@
+import importlib
+import inspect
+import os
+import pkgutil
+
+from docsgpt.agents.tools.base import Tool
+
+
+class ToolManager:
+    def __init__(self, config):
+        self.config = config
+        self.tools = {}
+        self.load_tools()
+
+    def load_tools(self):
+        tools_dir = os.path.join(os.path.dirname(__file__))
+        for finder, name, ispkg in pkgutil.iter_modules([tools_dir]):
+            if name == "base" or name.startswith("__"):
+                continue
+            module = importlib.import_module(f"docsgpt.agents.tools.{name}")
+            for member_name, obj in inspect.getmembers(module, inspect.isclass):
+                if issubclass(obj, Tool) and obj is not Tool and not obj.internal:
+                    tool_config = self.config.get(name, {})
+                    self.tools[name] = obj(tool_config)
+
+    def load_tool(self, tool_name, tool_config, user_id=None):
+        self.config[tool_name] = tool_config
+        module = importlib.import_module(f"docsgpt.agents.tools.{tool_name}")
+        for member_name, obj in inspect.getmembers(module, inspect.isclass):
+            if issubclass(obj, Tool) and obj is not Tool:
+                if (
+                    tool_name
+                    in {
+                        "mcp_tool",
+                        "notes",
+                        "memory",
+                        "todo_list",
+                        "scheduler",
+                        "remote_device",
+                        "code_executor",
+                        "artifact_generator",
+                        "read_document",
+                    }
+                    and user_id
+                ):
+                    return obj(tool_config, user_id)
+                else:
+                    return obj(tool_config)
+
+    def execute_action(self, tool_name, action_name, user_id=None, **kwargs):
+        if tool_name not in self.tools:
+            raise ValueError(f"Tool '{tool_name}' not loaded")
+        if (
+            tool_name
+            in {
+                "mcp_tool",
+                "memory",
+                "todo_list",
+                "notes",
+                "scheduler",
+                "remote_device",
+                "code_executor",
+                "artifact_generator",
+                "read_document",
+            }
+            and user_id
+        ):
+            tool_config = self.config.get(tool_name, {})
+            tool = self.load_tool(tool_name, tool_config, user_id)
+            return tool.execute_action(action_name, **kwargs)
+        return self.tools[tool_name].execute_action(action_name, **kwargs)
+
+    def get_all_actions_metadata(self):
+        metadata = []
+        for tool in self.tools.values():
+            metadata.extend(tool.get_actions_metadata())
+        return metadata