feat: add is_subagent flag to agents, fix all lint/type/test issues

- Add is_subagent checkbox to agent editor; subagents are hidden from Chat Settings
- Add is_subagent field to AgentDefinition type, TOML serialization, and API route
- Filter subagents from ModelSelector agent list
- Fix all biome lint/format errors across codebase (useLiteralKeys, noNonNullAssertion, noExplicitAny, formatting, import sorting)
- Fix svelte-check errors (type narrowing in SkillsBrowser, ToolPermissions, SidebarPanel)
- Fix a11y warnings in App.svelte (label-control associations)
- Fix test mocks missing BackgroundShellStore, BackgroundTranscriptStore, createWebSearchTool, createYoutubeTranscribeTool
- Update stale 409 test to match current message-queuing behavior
- Exclude packaging/ and release/ dirs from biome to avoid linting stale build artifacts

2 files changed, 6 insertions, 7 deletions

diff --git a/packages/api/src/routes/agents.ts b/packages/api/src/routes/agents.ts
index 42339bf..d3ca23f 100644
--- a/packages/api/src/routes/agents.ts
+++ b/packages/api/src/routes/agents.ts
@@ -56,6 +56,7 @@ agentsRoutes.post("/", async (c) => {
 			scope: body.scope,
 			slug: body.slug,
 			...(body.cwd ? { cwd: body.cwd } : {}),
+			...(body.is_subagent ? { is_subagent: true } : {}),
 		};
 		saveAgent(agent);
 		return c.json({ ok: true, agent });
diff --git a/packages/api/src/routes/models.ts b/packages/api/src/routes/models.ts
index d6b82c2..b250263 100644
--- a/packages/api/src/routes/models.ts
+++ b/packages/api/src/routes/models.ts
@@ -112,7 +112,7 @@ modelsRoutes.get("/available", async (c) => {
 		});
 	}
 
-	const apiKeyValue = resolveApiKey(keyId!);
+	const apiKeyValue = resolveApiKey(keyId);
 	if (!apiKeyValue) {
 		return c.json({ error: `no API key found for ${keyId}` }, 500);
 	}
@@ -420,10 +420,7 @@ modelsRoutes.post("/add-key", async (c) => {
 
 	// Validate provider
 	if (!VALID_PROVIDERS.includes(body.provider as SupportedProvider)) {
-		return c.json(
-			{ error: `provider must be one of: ${VALID_PROVIDERS.join(", ")}` },
-			400,
-		);
+		return c.json({ error: `provider must be one of: ${VALID_PROVIDERS.join(", ")}` }, 400);
 	}
 	const provider = body.provider as SupportedProvider;
 	const base_url = PROVIDER_BASE_URLS[provider];
@@ -452,7 +449,7 @@ modelsRoutes.post("/add-key", async (c) => {
 	newBlock += "\n";
 
 	// Insert before the # ─── Permissions section if it exists, otherwise at end
-	const permissionsMarker = /\n# [─\-]+ Permissions/;
+	const permissionsMarker = /\n# [─-]+ Permissions/;
 	let newContent: string;
 	const permMatch = permissionsMarker.exec(tomlContent);
 	if (permMatch) {
@@ -509,7 +506,8 @@ modelsRoutes.post("/remove-key", async (c) => {
 		return c.json({ error: `key "${id}" not found in dispatch.toml` }, 404);
 	}
 
-	const newContent = tomlContent.slice(0, match.index) + tomlContent.slice(match.index + match[0].length);
+	const newContent =
+		tomlContent.slice(0, match.index) + tomlContent.slice(match.index + match[0].length);
 
 	try {
 		writeFileSync(tomlPath, newContent, "utf-8");