feat(mcp): disable Playwright MCP by default (#77)

## Summary
Flip Playwright MCP's default \`enabled\` from \`true\` to \`false\`.
Browser tools become opt-in — neither the main agent nor the
browser-pilot crew sees \`browser_navigate\`, \`browser_click\`,
\`browser_screenshot\`, etc. until the user explicitly enables the
Playwright server from the MCP settings UI.

## Why
The main agent shouldn't reach for browser tools unprompted. The intent
is:
- Browser work → \`use_crew(\"browser-pilot\", ...)\` deliberately
- Main agent stays focused on orchestration

When the user enables Playwright via the UI, both the main agent and
browser-pilot get the tools back simultaneously (current architecture is
single shared MCP server, no per-crew scoping yet — that's a separate
larger change tracked elsewhere).

## Affected behaviour
- **Fresh installs**: no browser tools by default. User clicks Enable in
MCP settings → tools restored to both the main agent and browser-pilot.
- **Existing users**: their \`mcp.json\` already has \`enabled: true\`
from when they first installed; this PR doesn't migrate that. They keep
browser tools unless they manually disable.

## Test plan
- [x] \`npx tsc --noEmit\` clean
- [ ] Fresh install: confirm Playwright doesn't show in the agent's tool
list
- [ ] Enable Playwright from MCP settings: confirm \`browser_*\` tools
reappear, browser-pilot can run
- [ ] Disable again: confirm both surfaces lose the tools

Author: UmarFarooq75

src/mcp/defaults.ts

@@ -260,7 +260,7 @@ export const MCP_DEFAULTS: Readonly<Record<string, MCPDefault>> = {
     requiredEnv: ["UPSTASH_REDIS_REST_URL", "UPSTASH_REDIS_REST_TOKEN"],
   },
   playwright: {
-    description: "Browser control — Microsoft Playwright MCP. Persistent profile shared with `daemora browser` CLI logins.",
+    description: "Browser control — Microsoft Playwright MCP. Disabled by default; enable from MCP settings when you want browser tools available to the main agent and the browser-pilot crew. Persistent profile shared with `daemora browser` CLI logins.",
     config: {
       command: "npx",
       args: [
@@ -277,7 +277,12 @@ export const MCP_DEFAULTS: Readonly<Record<string, MCPDefault>> = {
         // so the profile path lives under the user's actual dataDir rather
         // than a placeholder. See MCPStore.load().
       ],
-      enabled: true,
+      // Off by default. The main agent shouldn't reach for browser tools
+      // unprompted — the intent is `use_crew("browser-pilot", ...)` for
+      // browser work, and the crew sees these tools only after the user
+      // explicitly enables this MCP server from the Settings UI. Once
+      // enabled, both the main agent and browser-pilot share it.
+      enabled: false,
     },
     docsUrl: "https://github.com/microsoft/playwright-mcp",
   },