## Pull request overview

## Pull request overview

Intended to revert the bubblewrap exit-code guard, but also includes unrelated sandbox, sessions, UI, configuration, and dependency changes.

**Changes:**
- Restores output-only bubblewrap host-restriction detection.
- Adds automatic AppArmor remediation and weaker nested-sandbox fallback.
- Bundles unrelated quick-chat, placeholder, BYOK, pet, and Markdown changes.

Show a summary per file

| File | Description |
| ---- | ----------- |
| `runInTerminalTool.test.ts` | Updates sandbox remediation tests. |
| `terminalSandboxService.test.ts` | Adds AppArmor status fixture. |
| `runInTerminalTool.ts` | Changes bubblewrap detection and remediation. |
| `chatInputPlaceholderRotation.ts` | Removes rotating placeholders. |
| `chatWidget.ts` | Removes placeholder rotation integration. |
| `chatPetWidget.ts` | Adds sprite conversion TODO. |
| `chatSlashCommands.ts` | Marks pet command experimental. |
| `SESSIONS.md` | Removes rotation documentation. |
| `localAgentHostSessionsProvider.test.ts` | Tests quick-chat promotion. |
| `openSubagentChat.css` | Refactors pill state styling. |
| `baseAgentHostSessionsProvider.ts` | Adds monotonic quick-chat promotion. |
| `AGENT_HOST_SESSIONS_PROVIDER.md` | Documents promotion behavior. |
| `slashCommands.ts` | Marks sessions pet command experimental. |
| `newChatInput.ts` | Retains static randomized placeholders. |
| `sandboxHelper.test.ts` | Tests AppArmor detection. |
| `terminalSandboxEngine.test.ts` | Tests weaker sandbox fallback. |
| `sandboxHelper.ts` | Reads AppArmor restriction state. |
| `terminalSandboxEngine.ts` | Enables weaker nested sandbox fallback. |
| `sandboxHelperService.ts` | Exposes AppArmor status. |
| `protocolServerHandler.test.ts` | Tests workspace-less metadata transport. |
| `agentService.test.ts` | Tests config-less quick-chat metadata. |
| `remoteAgentHostProtocolClient.test.ts` | Tests metadata round-trip. |
| `protocolServerHandler.ts` | Serializes session metadata. |
| `agentService.ts` | Tags config-less sessions workspace-less. |
| `agentHostStarter.config.contribution.ts` | Disables BYOK models by default. |
| `remoteAgentHostProtocolClient.ts` | Preserves listed session metadata. |
| `placeholderTextContribution.ts` | Removes placeholder animation support. |
| `placeholderText.css` | Removes shimmer animation styles. |
| `package.json` | Updates Markdown editor dependency. |
| `package-lock.json` | Locks the updated dependency. |
| `.github/skills/sessions/SKILL.md` | Updates quick-chat guidance. |

## Review details

- **Files reviewed:** 8/8 changed files
- **Comments generated:** 2
- **Review effort level:** Medium

_Originally posted by @Copilot in https://github.com/microsoft/vscode/pull/327766#pullrequestreview-4794273543_