test: replaced blind sleeps with shared fixtures and condition polling

- Shared immutable model registries and auth storage via beforeAll/afterAll.
- Swapped fixed-delay settle sleeps for predicate polling and signals.
- Stubbed network/timers to drop wall-clock waits in registry and history tests.
- Added resetDisplay invalidation tests and startup-timing breakdown lines.

packages/coding-agent/test/agent-session-python-cleanup.test.ts

@@ -116,6 +116,7 @@ const createSession = async (
 			disableExtensionDiscovery: true,
 			extensions: options.extensions,
 			skills: [],
+			rules: [],
 			contextFiles: [],
 			promptTemplates: [],
 			workspaceTree: emptyWorkspaceTree(cwd),
@@ -195,6 +196,7 @@ describe("AgentSession python cleanup", () => {
 				disableExtensionDiscovery: true,
 				extensions: [throwingExtension],
 				skills: [],
+				rules: [],
 				contextFiles: [],
 				promptTemplates: [],
 				slashCommands: [],
@@ -261,6 +263,7 @@ describe("AgentSession python cleanup", () => {
 				model: getModel(),
 				disableExtensionDiscovery: true,
 				skills: [],
+				rules: [],
 				contextFiles: [],
 				promptTemplates: [],
 				slashCommands: [],