refactor: wave 2 - split atlas, auto-update-checker, session-recovery, todo-enforcer, background-task hooks

- Extract atlas/ into 15 focused modules (hook, event handler, tool policies, types, etc.)
- Split auto-update-checker into checker/ and hook/ subdirectories with single-purpose files
- Decompose session-recovery into separate recovery strategy files per error type
- Extract todo-continuation-enforcer from monolith to directory with dedicated modules
- Split background-task/tools.ts into individual tool creator files
- Extract command-executor, tmux-utils into focused sub-modules
- Split config/schema.ts into domain-specific schema files
- Decompose cli/config-manager.ts into focused modules
- Rollback skill-mcp-manager, model-availability, index.ts splits that broke tests
- Fix all import path depths for moved files (../../ -> ../../../)
- Add explicit type annotations to resolve TS7006 implicit any errors

Typecheck: 0 errors
Tests: 2359 pass, 5 fail (all pre-existing)

src/hooks/atlas/recent-model-resolver.ts

@@ -0,0 +1,38 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+import { findNearestMessageWithFields } from "../../features/hook-message-injector"
+import { getMessageDir } from "../../shared/session-utils"
+import type { ModelInfo } from "./types"
+
+export async function resolveRecentModelForSession(
+  ctx: PluginInput,
+  sessionID: string
+): Promise<ModelInfo | undefined> {
+  try {
+    const messagesResp = await ctx.client.session.messages({ path: { id: sessionID } })
+    const messages = (messagesResp.data ?? []) as Array<{
+      info?: { model?: ModelInfo; modelID?: string; providerID?: string }
+    }>
+
+    for (let i = messages.length - 1; i >= 0; i--) {
+      const info = messages[i].info
+      const model = info?.model
+      if (model?.providerID && model?.modelID) {
+        return { providerID: model.providerID, modelID: model.modelID }
+      }
+
+      if (info?.providerID && info?.modelID) {
+        return { providerID: info.providerID, modelID: info.modelID }
+      }
+    }
+  } catch {
+    // ignore - fallback to message storage
+  }
+
+  const messageDir = getMessageDir(sessionID)
+  const currentMessage = messageDir ? findNearestMessageWithFields(messageDir) : null
+  const model = currentMessage?.model
+  if (!model?.providerID || !model?.modelID) {
+    return undefined
+  }
+  return { providerID: model.providerID, modelID: model.modelID }
+}