refactor(connector): rewrite catalog registry as pure pi-mono shape

Strips adapter module, defaultCommand, listModels, configurationDoc,
capabilityMatrix, and notes fields from the ConnectorDefinition type.
What remains is the declarative pi-mono shape: id, provider, label,
description, defaultModel, auth descriptor, onboardingFeatured, notes.

The three data files are imported and spread into the CONNECTORS array.
findConnectorDefinition + listFeaturedOnboardingConnectors stay in the
lookup module unchanged. Docs builders still provide buildOAuthDoc /
buildApiKeyDoc / buildCloudDoc for the Settings panel and are consumed
by connectors.ts when synthesising per-row configuration docs.

ConnectorAuth now uses `type` as the discriminator (legacy `kind` alias
removed — credential-resolver and ipc-credentials-handlers already keyed
off `type`).

src/main/connector-definitions-docs.ts

@@ -0,0 +1,38 @@
+/**
+ * Per-auth-kind configuration documentation builders for the Settings →
+ * Providers panel. Extracted from `connector-definitions.ts` to keep that
+ * file under the 400-line cap.
+ */
+
+import type { PiOAuthProviderId } from "./connector-definitions";
+
+export function buildOAuthDoc(label: string, oauthId: PiOAuthProviderId): string {
+  return [
+    `# ${label}`,
+    "",
+    "Authenticate via OAuth in your system browser. AgentCompany opens",
+    "the provider's authorization page; the redirect handler runs locally on",
+    "`http://localhost:53692/callback`.",
+    "",
+    `OAuth provider id: \`${oauthId}\`.`,
+    "",
+    "Tokens are encrypted by the OS keychain (or per-profile vault) and",
+    "stored in the `credentials` table. Tokens are refreshed automatically",
+    "before each run (60 second window).",
+  ].join("\n");
+}
+
+export function buildApiKeyDoc(label: string, envVar: string): string {
+  return [
+    `# ${label}`,
+    "",
+    `API key authentication. Either paste the literal key or use a system`,
+    `environment variable name (default: \`${envVar}\`).`,
+    "",
+    "Keys are encrypted at rest via OS keychain (or per-profile vault).",
+  ].join("\n");
+}
+
+export function buildCloudDoc(label: string, body: string): string {
+  return [`# ${label}`, "", body].join("\n");
+}