Document QueryCollection clearError() throwing behavior

Relates to: PR #441 ("add error tracking and retry methods to query collection utils")
Scope: Documentation / DX
Breaking changes: None (documenting existing behavior)

Summary

QueryCollection.utils.clearError() can throw errors when the refetch fails, but this behavior is not documented. Users need clear guidance on proper error handling patterns.

Current Implementation

// In packages/query-db-collection/src/query.ts:735-740
clearError: () => {
  lastError = undefined
  errorCount = 0
  lastErrorUpdatedAt = 0
  return refetch({ throwOnError: true }) // This can throw!
}

The method does throw on refetch failure, but this isn't documented anywhere.

Proposed Documentation

Add to error handling guide and JSDoc:

/**
 * Clear the error state and trigger a refetch of the query
 * @returns Promise that resolves when the refetch completes successfully
 * @throws Error if the refetch fails
 * @example
 * try {
 *   await collection.utils.clearError()
 *   // success: error state cleared; data refreshed
 * } catch (e) {
 *   // still in error; show toast/backoff, etc.
 * }
 */
clearError: () => Promise<void>

Acceptance Criteria

• Error handling guide explicitly states that clearError() throws on failure
• JSDoc includes @throws annotation with example
• Example uses try/catch pattern
• Document interaction with disabled queries (when combined with exact refetch targeting)
• Add to QueryCollectionUtils interface documentation

Additional Context

This is especially important when combined with the exact refetch targeting (#537), as disabled/unobserved queries may behave differently.

Start by reading packages/query-db-collection/src/query.ts around lines 735-740 and the QueryCollectionUtils interface documentation to confirm clearError() behavior. Locate the error handling guide and review the disabled-query and exact-refetch context from the issue. Done means the guide, JSDoc, interface documentation, and try/catch example all explain successful refetches and thrown failures.