Structure view groupings UI

[BoykoAlex]

Fixes #1629

[Copilot]

Pull Request Overview

Adds “Structure view groupings” to the Spring explorer: users can select which groups to show per project, with choices persisted per workspace.

• Introduces a “Select Groups to Show/Hide” command tied to project nodes in the Spring explorer.
• Persists per-project visible groups and sends them to the language server to shape the structure view.
• Refactors explorer tree initialization and expansion-state tracking into the provider.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
vscode-extensions/vscode-spring-boot/package.json	Adds a project-node context menu item and command for group selection.
vscode-extensions/vscode-spring-boot/lib/explorer/structure-tree-manager.ts	Registers commands, persists group selections, and passes group filters to the LS.
vscode-extensions/vscode-spring-boot/lib/explorer/nodes.ts	Marks project nodes with a distinct context value (“project”) for menu targeting.
vscode-extensions/vscode-spring-boot/lib/explorer/explorer-tree-provider.ts	Adds a createTreeView helper and internalizes expansion-state tracking.
vscode-extensions/vscode-spring-boot/lib/copilot/copilotRequest.ts	Removes verbose request logging.
vscode-extensions/vscode-spring-boot/lib/Main.ts	Activates the structure explorer via the new provider API and manager.
headless-services/.../StructureViewUtil.java	Accepts Collection for group filters.
headless-services/.../SpringIndexCommands.java	Extends command args to per-project group maps, adds groups query command; parsing and return handling updated.
headless-services/.../ModulithStructureView.java	Accepts Collection for group filters.
headless-services/.../JMoleculesStructureView.java	Accepts Collection for group filters.

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[Copilot]

Gson#fromJson requires a Type for generic deserialization. Pass the Type from the TypeToken using .getType(), otherwise this code will not compile and will not deserialize correctly.

Suggested change

	selectedGroups = new Gson().fromJson(groupsElement, new TypeToken<Map<String, Set<String>>>() {});
	selectedGroups = new Gson().fromJson(groupsElement, new TypeToken<Map<String, Set<String>>>() {}.getType());