feat: agent builder, CWD support, auto-save, UI polish, unavailable tool handling

- Agent Builder: full CRUD with card grid, drag-and-drop model reorder, edit/delete
- Auto-save on edit with 600ms debounce, AbortController for concurrency, fieldset disabled until name entered
- Agent definitions stored as TOML with cwd field, loaded from global/project dirs
- Working directory: per-tab CWD override in Chat Settings, agent default CWD, auto-create on first message
- CWD validation: check-dir endpoint with ~ expansion, real-time validity indicator
- Subagent CWD validated against parent's effective CWD using path.relative
- Unavailable tool calls: caught gracefully, shown as tool call with error badge, model retries
- UI: tab bar border radius, sidebar border removed, chat input ghost style, scroll-to-bottom rectangle
- Skills dir collapse uses CSS rotation, Model Choice renamed to Chat Settings, System Prompt view removed
- Reusable SkillsBrowser/ToolPermissions with external mode for Agent Builder
- ModelSelector: Agent/Manual toggle, agent list, Agent Settings link
- Page router, skills recursive scanning, bin/up gopass removed, docker volume mounts

1 files changed, 3 insertions, 1 deletions

diff --git a/packages/core/src/db/settings.ts b/packages/core/src/db/settings.ts
index 51d6ea2..f9d152e 100644
--- a/packages/core/src/db/settings.ts
+++ b/packages/core/src/db/settings.ts
@@ -2,7 +2,9 @@ import { getDatabase } from "./index.js";
 
 export function getSetting(key: string): string | null {
 	const db = getDatabase();
-	const row = db.query("SELECT value FROM settings WHERE key = $key").get({ $key: key }) as { value: string } | null;
+	const row = db.query("SELECT value FROM settings WHERE key = $key").get({ $key: key }) as {
+		value: string;
+	} | null;
 	return row?.value ?? null;
 }