fix(cc-config): .claude.json sits BESIDE ~/.claude by default, not inside it

The previous commit routed the read through getClaudeHome(), which appends
/.claude when CLAUDE_HOME is unset — pointing the dashboard at
~/.claude/.claude.json, a file the CLI never writes by default. Verified
against the real binary: with CLAUDE_CONFIG_DIR unset the CLI writes
$HOME/.claude.json; with it set, .claude.json sits flat inside that dir.
Branch on CLAUDE_HOME accordingly.

The test now drives a fake claude that writes where the real one does and
asserts getClaudeJsonPath() names that exact file, under both branches —
the previous test only restated the implementation.

server/openapi-extra/cc-config.js

@@ -327,6 +327,12 @@ const schemas = {
           "Where the definition was found, e.g. `~/.claude.json (top-level)`, `~/.claude.json (projects[<root>])`, or `~/.claude/settings.json`.",
         example: "~/.claude.json (top-level)",
       },
+      removable: {
+        type: "boolean",
+        description:
+          "False when no `claude mcp` scope can address this entry (currently only ~/.claude/settings.json-sourced servers), so POST /mcp/remove has no scope that would find it. Absent/true means removable.",
+        example: true,
+      },
       kind: {
         type: "string",
         enum: ["http", "stdio", "unknown"],