feat: remove proxyMode — all traffic goes through mcplocal proxy

proxyMode "direct" was a security hole (leaked secrets as plaintext env
vars in .mcp.json) and bypassed all mcplocal features (gating, audit,
RBAC, content pipeline, namespacing). Removed from schema, API, CLI,
and all tests. Old configs with proxyMode are accepted but silently
stripped via Zod .transform() for backward compatibility.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli/tests/commands/get.test.ts

@@ -179,7 +179,6 @@ describe('get command', () => {
       id: 'proj-1',
       name: 'smart-home',
       description: 'Home automation',
-      proxyMode: 'filtered',
       ownerId: 'usr-1',
       servers: [{ server: { name: 'grafana' } }],
     }]);
@@ -187,10 +186,8 @@ describe('get command', () => {
     await cmd.parseAsync(['node', 'test', 'projects']);
 
     const text = deps.output.join('\n');
-    expect(text).toContain('MODE');
     expect(text).toContain('SERVERS');
     expect(text).toContain('smart-home');
-    expect(text).toContain('filtered');
     expect(text).toContain('1');
   });
 
@@ -341,7 +338,6 @@ describe('get command', () => {
       id: 'proj-1',
       name: 'home',
       description: '',
-      proxyMode: 'direct',
       proxyModel: '',
       gated: true,
       ownerId: 'usr-1',
@@ -362,7 +358,6 @@ describe('get command', () => {
       id: 'proj-1',
       name: 'home',
       description: '',
-      proxyMode: 'direct',
       proxyModel: '',
       gated: true,
       ownerId: 'usr-1',
@@ -381,7 +376,6 @@ describe('get command', () => {
       id: 'proj-1',
       name: 'tools',
       description: '',
-      proxyMode: 'direct',
       proxyModel: '',
       gated: false,
       ownerId: 'usr-1',
@@ -400,7 +394,6 @@ describe('get command', () => {
       id: 'proj-1',
       name: 'custom',
       description: '',
-      proxyMode: 'direct',
       proxyModel: 'gate',
       gated: true,
       ownerId: 'usr-1',