fix(atlas,todo-continuation): strip ZWSP sort prefix before promptAsync agent

Both injectors call resolveRegisteredAgentName, which returns the
registered alias verbatim. OpenCode TUI registers agent names with
leading zero-width characters (U+200B) for sort ordering, so that
alias can be e.g. "\u200B\u200BAtlas - Plan Executor". Passing it
directly to promptAsync produces "Agent not found" because the
OpenCode SDK does an exact match against its canonical display
name registry.

Strip the ZWSP sort prefix on the resolved name before sending it
to promptAsync in:
- src/hooks/atlas/boulder-continuation-injector.ts
- src/hooks/todo-continuation-enforcer/continuation-injection.ts

Add regression tests asserting promptAsync receives the canonical
display name (no \u200B) even when the registered alias carries
a ZWSP sort prefix. Same root cause class as #3494 / #3547. Tests
were RED on dev before the fix and GREEN after.

src/hooks/todo-continuation-enforcer/continuation-injection.test.ts

@@ -43,6 +43,45 @@ describe("injectContinuation", () => {
     expect(capturedAgent).toBe("Sisyphus - Ultraworker")
   })
 
+  test("#given resolved agent name still carries a ZWSP sort prefix #when continuation is injected #then promptAsync receives the agent name without the ZWSP prefix", async () => {
+    // given
+    let capturedAgent: string | undefined
+    const ctx = {
+      directory: "/tmp/test",
+      client: {
+        session: {
+          todo: async () => ({ data: [{ id: "1", content: "todo", status: "pending", priority: "high" }] }),
+          promptAsync: async (input: {
+            body: {
+              agent?: string
+            }
+          }) => {
+            capturedAgent = input.body.agent
+            return {}
+          },
+        },
+      },
+    }
+    const sessionStateStore = {
+      getExistingState: () => ({ inFlight: false, lastInjectedAt: 0, consecutiveFailures: 0 }),
+    }
+
+    // when
+    await injectContinuation({
+      ctx: ctx as never,
+      sessionID: "ses_zwsp_agent",
+      resolvedInfo: {
+        agent: "\u200B\u200BSisyphus - Ultraworker",
+        model: { providerID: "anthropic", modelID: "claude-sonnet-4-20250514" },
+      },
+      sessionStateStore: sessionStateStore as never,
+    })
+
+    // then
+    expect(capturedAgent).toBe("Sisyphus - Ultraworker")
+    expect(capturedAgent).not.toContain("\u200B")
+  })
+
   test("inherits tools from resolved message info when reinjecting", async () => {
     // given
     let capturedTools: Record<string, boolean> | undefined

src/hooks/todo-continuation-enforcer/continuation-injection.ts

@@ -20,6 +20,7 @@ import { isSqliteBackend } from "../../shared/opencode-storage-detection"
 import {
   getAgentConfigKey,
   normalizeAgentForPromptKey,
+  stripAgentListSortPrefix,
 } from "../../shared/agent-display-names"
 import { promptAsyncAfterSessionIdle } from "../shared/prompt-async-gate"
 
@@ -131,7 +132,8 @@ export async function injectContinuation(args: {
   }
 
   const promptAgent = normalizeAgentForPromptKey(agentName)
-  const launchAgent = resolveRegisteredAgentName(agentName)
+  const resolvedAgent = resolveRegisteredAgentName(agentName)
+  const launchAgent = resolvedAgent ? stripAgentListSortPrefix(resolvedAgent) : resolvedAgent
 
   if (promptAgent && skipAgents.some(s => getAgentConfigKey(s) === getAgentConfigKey(promptAgent))) {
     log(`[${HOOK_NAME}] Skipped: agent in skipAgents list`, { sessionID, agent: agentName })