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/boulder-continuation-injector.ts

@@ -0,0 +1,68 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+import type { BackgroundManager } from "../../features/background-agent"
+import { log } from "../../shared/logger"
+import { HOOK_NAME } from "./hook-name"
+import { BOULDER_CONTINUATION_PROMPT } from "./system-reminder-templates"
+import { resolveRecentModelForSession } from "./recent-model-resolver"
+import type { SessionState } from "./types"
+
+export async function injectBoulderContinuation(input: {
+  ctx: PluginInput
+  sessionID: string
+  planName: string
+  remaining: number
+  total: number
+  agent?: string
+  backgroundManager?: BackgroundManager
+  sessionState: SessionState
+}): Promise<void> {
+  const {
+    ctx,
+    sessionID,
+    planName,
+    remaining,
+    total,
+    agent,
+    backgroundManager,
+    sessionState,
+  } = input
+
+  const hasRunningBgTasks = backgroundManager
+    ? backgroundManager.getTasksByParentSession(sessionID).some((t: { status: string }) => t.status === "running")
+    : false
+
+  if (hasRunningBgTasks) {
+    log(`[${HOOK_NAME}] Skipped injection: background tasks running`, { sessionID })
+    return
+  }
+
+  const prompt =
+    BOULDER_CONTINUATION_PROMPT.replace(/{PLAN_NAME}/g, planName) +
+    `\n\n[Status: ${total - remaining}/${total} completed, ${remaining} remaining]`
+
+  try {
+    log(`[${HOOK_NAME}] Injecting boulder continuation`, { sessionID, planName, remaining })
+
+    const model = await resolveRecentModelForSession(ctx, sessionID)
+
+    await ctx.client.session.promptAsync({
+      path: { id: sessionID },
+      body: {
+        agent: agent ?? "atlas",
+        ...(model !== undefined ? { model } : {}),
+        parts: [{ type: "text", text: prompt }],
+      },
+      query: { directory: ctx.directory },
+    })
+
+    sessionState.promptFailureCount = 0
+    log(`[${HOOK_NAME}] Boulder continuation injected`, { sessionID })
+  } catch (err) {
+    sessionState.promptFailureCount += 1
+    log(`[${HOOK_NAME}] Boulder continuation failed`, {
+      sessionID,
+      error: String(err),
+      promptFailureCount: sessionState.promptFailureCount,
+    })
+  }
+}