feat(server): add groups/list and groups/get MCP methods - #3583

Embed the initialized Toolset and Promptset in Group instead of
flattening their fields, so ToToolset/ToPromptset return the views
with their lookup sets intact rather than rebuilding them per call.

Replace the toolset/promptset maps with an authoritative groups map and
derive the toolset/promptset views from it via ToToolset/ToPromptset.
Legacy kind: toolsets configs convert to tools-only groups at init, and
the default nameless group holds all tools and prompts. No YAML surface
change; kind: groups parsing is deferred to a follow-up.

…et views

Add parsing for `kind: group` documents (flat and nested `groups:`
blocks) in UnmarshalResourceConfig, returning parsed GroupConfigs.
Validate duplicate default/named groups and reject a default group
that declares tools or prompts. Wire GroupConfigs through config
merge, reload, and initializeGroups so kind: group definitions
override same-named toolsets.

The MCP route is /{toolsetName}, so promptsetName was always empty and
GetPromptset("") returned all prompts regardless of the connected group.
Resolve the group by its URL name and use its derived toolset/promptset
views so prompts/list scopes per group.

Expose group introspection across all five protocol versions. groups/list
returns named groups with descriptions, omitting the default nameless group.
groups/get returns a named group's tools and prompts.

…ring

# Conflicts:
#	internal/group/group.go

…coping

Pass the resolved group.Group through ProcessMethod and the version
handlers instead of materialized toolset/promptset views. List handlers
now read ToolNames/PromptNames directly from the group, which scopes
prompts to a single group and fixes the always-empty promptset lookup.

…trospection

# Conflicts:
#	internal/server/mcp/v20241105/method.go
#	internal/server/mcp/v20250326/method.go
#	internal/server/mcp/v20250618/method.go
#	internal/server/mcp/v20251125/method.go
#	internal/server/mcp/vdraft/method.go

…coping

…trospection

…3575)

## Description

Adds parsing for `kind: group` configuration documents and wires the
parsed groups through initialization. Groups are the source of truth
from which toolset and promptset views are derived; this PR lets users
declare them directly in config.

- `UnmarshalResourceConfig` now parses both flat (`kind: group`) and
nested (`groups:`) formats, returning a new `GroupConfigs` value.
- Validation: rejects duplicate default (nameless) or named groups, and
rejects a default group that declares `tools` or `prompts` (it always
contains all configured tools and prompts).
- `GroupConfigs` flows through config merge, dynamic reload, and
`initializeGroups`; a `kind: group` definition overrides a same-named
toolset (with a warning).
- Mechanically updated all `UnmarshalResourceConfig` call sites for the
new return arity.

Stacked on #3569

---------

Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com>

…at/groups-pr2-prompt-scoping

# Conflicts:
#	cmd/internal/config.go
#	cmd/internal/config_test.go
#	internal/server/config.go
#	internal/server/server.go
#	internal/server/server_test.go

…ompt-scoping test

Rename the toolsetName Go identifier to groupName across the SSE and message
handlers and processMcpMessage, since the value now names a group. The
"toolsetName" route key and toolset.name telemetry attributes are unchanged.
Add a doc comment to TestMcpPromptScopingByGroup clarifying it is an
end-to-end test, distinct from the manifests_test.go unit test.

Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com>

Rename GroupDescription to Group across all five MCP version packages
(v20241105, v20250326, v20250618, v20251125, vdraft) to match MCP type
conventions, and add prompts-style debug logging to groupsListHandler and
groupsGetHandler. Update group handler tests to inject a logger into context.

…trospection