Spec: the fake uses the SDK's server API from ModelContextProtocol.Core and gains the tools and modes the tests need (weird_name_x, a >48-char name, builtin-clash, --output-dir browser tools, die message and exit code, count-starts details, slow cancellation log).
McpOptions/McpServerConfig/PlaywrightOptions with ApplyEnvironment (PLAYWRIGHT_* variables, quote-aware ExtraArgs split) and Validate; ShellWords; mcpServers from the user settings.json. New project in the solution and referenced by the extension tests.
Adds the GoogleCalendar extension project (Abstractions only, Private=false), GoogleCalendarOptions with
env fallbacks and a secret-free ToString, GoogleCalendarException/Messages, ChatKeys (scope -> safe directory
name), StoredToken and GoogleTokenStore (atomic write, owner-only on Unix, reads never throw), and an empty
GoogleCalendarConnections stub for Task 3. The test project gains the extension reference and
Microsoft.Extensions.TimeProvider.Testing 10.9.0.
HostProcessHardening calls prctl(PR_SET_DUMPABLE, 0) through LibraryImport, once per process, from the ProcessSpawnPolicy constructor, and warns when DOTNET_EnableDiagnostics is not 0. Test projects consume the one-shot call with the flag off in a module initializer. A HardeningProbe helper backs a Linux-only /proc integration test.
