feat: resolve final 3 medium audit issues

TS-01: Extracted 33 shared interfaces to src/types/arcane-types.ts,
updated 21 tool files to use import type instead of local definitions.

PERF-01: McpServer template pattern — register tools once, share
definitions across HTTP sessions via reference copy. Eliminates
180 re-registrations per session.

TEST-03: Added 29 integration tests (79 total across 8 files):
- container-tools (7 tests), dashboard-tools (6 tests)
- resources (7 tests), prompts (9 tests)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: RandomSynergy17

src/resources/__tests__/resources.test.ts

@@ -127,7 +127,7 @@ describe("resources", () => {
     });
 
     it("shows 'not set' when no default environment", async () => {
-      mockClient.getDefaultEnvironmentId.mockReturnValueOnce(undefined);
+      mockClient.getDefaultEnvironmentId.mockReturnValueOnce(undefined as unknown as string);
 
       const handler = server.resources.get("arcane-version")!;
       const result = await handler(new URL("arcane://version"));