fix(background): Wave 2 - fix interrupt status checks, display text, error recovery grace, LSP JSONC

- fix(background): include "interrupt" status in all terminal status checks (3 files)
- fix(background): display "INTERRUPTED" instead of "CANCELLED" for interrupted tasks
- fix(cli): add error recovery grace period in poll-for-completion
- fix(lsp): use JSONC parser for config loading to support comments

All changes verified with tests and typecheck.

src/cli/run/poll-for-completion.ts

@@ -5,6 +5,7 @@ import { checkCompletionConditions } from "./completion"
 
 const DEFAULT_POLL_INTERVAL_MS = 500
 const DEFAULT_REQUIRED_CONSECUTIVE = 3
+const ERROR_GRACE_CYCLES = 3
 
 export interface PollOptions {
   pollIntervalMs?: number
@@ -21,19 +22,28 @@ export async function pollForCompletion(
   const requiredConsecutive =
     options.requiredConsecutive ?? DEFAULT_REQUIRED_CONSECUTIVE
   let consecutiveCompleteChecks = 0
+  let errorCycleCount = 0
 
   while (!abortController.signal.aborted) {
     await new Promise((resolve) => setTimeout(resolve, pollIntervalMs))
 
     // ERROR CHECK FIRST — errors must not be masked by other gates
     if (eventState.mainSessionError) {
-      console.error(
-        pc.red(`\n\nSession ended with error: ${eventState.lastError}`)
-      )
-      console.error(
-        pc.yellow("Check if todos were completed before the error.")
-      )
-      return 1
+      errorCycleCount++
+      if (errorCycleCount >= ERROR_GRACE_CYCLES) {
+        console.error(
+          pc.red(`\n\nSession ended with error: ${eventState.lastError}`)
+        )
+        console.error(
+          pc.yellow("Check if todos were completed before the error.")
+        )
+        return 1
+      }
+      // Continue polling during grace period to allow recovery
+      continue
+    } else {
+      // Reset error counter when error clears (recovery succeeded)
+      errorCycleCount = 0
     }
 
     if (!eventState.mainSessionIdle) {