refactor: wave 1 - extract leaf modules, rename catch-all files, split index.ts hooks

- Split 25+ index.ts files into hook.ts + extracted modules
- Rename all catch-all utils.ts/helpers.ts to domain-specific names
- Split src/tools/lsp/ into ~15 focused modules
- Split src/tools/delegate-task/ into ~18 focused modules
- Separate shared types from implementation
- 155 files changed, 60+ new files created
- All typecheck clean, 61 tests pass

src/tools/delegate-task/sync-session-creator.ts

@@ -0,0 +1,30 @@
+import type { OpencodeClient } from "./types"
+
+export async function createSyncSession(
+  client: OpencodeClient,
+  input: { parentSessionID: string; agentToUse: string; description: string; defaultDirectory: string }
+): Promise<{ ok: true; sessionID: string; parentDirectory: string } | { ok: false; error: string }> {
+  const parentSession = client.session.get
+    ? await client.session.get({ path: { id: input.parentSessionID } }).catch(() => null)
+    : null
+  const parentDirectory = parentSession?.data?.directory ?? input.defaultDirectory
+
+  const createResult = await client.session.create({
+    body: {
+      parentID: input.parentSessionID,
+      title: `${input.description} (@${input.agentToUse} subagent)`,
+      permission: [
+        { permission: "question", action: "deny" as const, pattern: "*" },
+      ],
+    } as any,
+    query: {
+      directory: parentDirectory,
+    },
+  })
+
+  if (createResult.error) {
+    return { ok: false, error: `Failed to create session: ${createResult.error}` }
+  }
+
+  return { ok: true, sessionID: createResult.data.id, parentDirectory }
+}