docs: Add IAsyncEnumerable gitbook documentation for task CEs (#350)

* Initial plan

* Add IAsyncEnumerable documentation to task CE gitbook docs

Co-authored-by: TheAngryByrd <1490044+TheAngryByrd@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: TheAngryByrd <1490044+TheAngryByrd@users.noreply.github.com>

Author: Copilot

gitbook/taskOption/ce.md

@@ -24,3 +24,25 @@ let addResult = taskOption {
   do! updatePerson person
 }
 ```
+
+### Example 2 - IAsyncEnumerable
+
+The `taskOption` CE supports `for .. in ..` iteration over `IAsyncEnumerable<'T>` sequences. Iteration stops immediately when the body returns `None`, without consuming further elements.
+
+```fsharp
+tryProcessItem : Item -> Task<unit option>
+getItemsAsync : unit -> IAsyncEnumerable<Item>
+```
+
+```fsharp
+// Task<string option>
+let processItems () =
+  taskOption {
+    for item in getItemsAsync () do
+      do! tryProcessItem item
+    return "done"
+  }
+// Returns None and stops iteration on the first None result
+```
+
+The `backgroundTaskOption` CE inherits this support automatically.

gitbook/taskResult/ce.md

@@ -33,3 +33,27 @@ let login (username: string) (password: string) : Task<Result<AuthToken, LoginEr
     return! user |> createAuthToken |> Result.mapError TokenErr
   }
 ```
+
+### Example 2 - IAsyncEnumerable
+
+The `taskResult` CE supports `for .. in ..` iteration over `IAsyncEnumerable<'T>` sequences. Iteration stops immediately when the body returns an `Error`, without consuming further elements.
+
+```fsharp
+validate : Item -> Task<Result<ValidItem, string>>
+save : ValidItem -> Task<Result<unit, string>>
+getItemsAsync : unit -> IAsyncEnumerable<Item>
+```
+
+```fsharp
+// Task<Result<string, string>>
+let processItems () =
+  taskResult {
+    for item in getItemsAsync () do
+      let! validated = validate item
+      do! save validated
+    return "done"
+  }
+// Stops iteration immediately on the first Error
+```
+
+The `backgroundTaskResult` CE inherits this support automatically.

gitbook/taskValidation/ce.md

@@ -39,3 +39,27 @@ let addResult = taskValidation {
 
 // task { return Error [ "Am"; "I"; "async?" ] }
 ```
+
+### IAsyncEnumerable
+
+The `taskValidation` CE supports `for .. in ..` iteration over `IAsyncEnumerable<'T>` sequences. Iteration stops immediately when the body returns an `Error`, without consuming further elements.
+
+```fsharp
+validate : Item -> Task<Result<ValidItem, string>>
+save : ValidItem -> Task<Result<unit, string>>
+getItemsAsync : unit -> IAsyncEnumerable<Item>
+```
+
+```fsharp
+// Task<Result<string, string list>>
+let processItems () =
+  taskValidation {
+    for item in getItemsAsync () do
+      let! validated = validate item
+      do! save validated
+    return "done"
+  }
+// Stops iteration immediately on the first Error
+```
+
+The `backgroundTaskValidation` CE inherits this support automatically.

gitbook/taskValueOption/ce.md

@@ -24,3 +24,25 @@ let addResult = taskValueOption {
   do! updatePerson person
 }
 ```
+
+### Example 2 - IAsyncEnumerable
+
+The `taskValueOption` CE supports `for .. in ..` iteration over `IAsyncEnumerable<'T>` sequences. Iteration stops immediately when the body returns `ValueNone`, without consuming further elements.
+
+```fsharp
+tryProcessItem : Item -> Task<unit voption>
+getItemsAsync : unit -> IAsyncEnumerable<Item>
+```
+
+```fsharp
+// Task<string voption>
+let processItems () =
+  taskValueOption {
+    for item in getItemsAsync () do
+      do! tryProcessItem item
+    return "done"
+  }
+// Returns ValueNone and stops iteration on the first ValueNone result
+```
+
+The `backgroundTaskValueOption` CE inherits this support automatically.