Fix Beam docs: compilation order, typo, and accuracy improvements

- Fix erlc compilation order in getting-started guide (runtime before user code)
- Fix extra quote typo in compatibility table
- Add link to Build and Run from getting-started page
- Move nativeOnly section to top of Utilities for better discoverability
- Clarify task/async equivalence and limitations on Beam
- Fix inaccurate claim about integer handling vs Python target

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dbrattli

docs/docs/beam/compatibility.md

@@ -40,7 +40,7 @@ Numeric Types                          | Native integers and floats
 Arrays                                 | Process dict refs (lists / atomics for byte[])
 System.Boolean                         | `true` / `false` atoms
 System.Char                            | Binary (string of length 1)
-System.String                          | Binary (`<<"...">>`")
+System.String                          | Binary (`<<"...">>`)
 System.Decimal                         | Custom fixed-scale integer
 System.DateTime                        | `{Ticks, Kind}` tuple
 System.DateTimeOffset                  | `{Ticks, OffsetTicks, Kind}` tuple
@@ -124,12 +124,12 @@ float32 / single | Single     | `float()`    | Native IEEE 754
 decimal          | Decimal    | Custom       | Fixed-scale integer implementation
 bigint           | BigInteger | `integer()`  | Native (Erlang integers ARE arbitrary-precision)
 
-### Erlang Advantage: No Wrapper Types Needed
+### Sized Integer Overflow
 
-Unlike the Python target which requires custom PyO3/Rust wrapper types for sized integers (~1200 lines), Erlang handles all integer operations natively. Sized integer wrapping (when needed for overflow semantics) uses Erlang's bit syntax:
+Like Python, Erlang has native arbitrary-precision integers. Sized integer wrapping (for overflow semantics of `int32`, `int64`, etc.) uses Erlang's bit syntax:
 
 ```erlang
-%% Wrapping int32 arithmetic — pure Erlang, no NIF
+%% Wrapping int32 arithmetic
 wrap32(N) ->
     <<V:32/signed-integer>> = <<N:32/signed-integer>>,
     V.
@@ -159,6 +159,10 @@ F#                          | Erlang
 `Async.Sleep`               | `timer:sleep(Ms)`
 `task { return x }`         | Same as async (alias on Beam)
 
+:::info
+`task { }` and `async { }` compile to the same CPS representation on Beam. The hot-start semantics of .NET `Task` are not preserved. Downcasting from `obj` to `Task<T>` or `Async<T>` is not supported.
+:::
+
 ### CancellationToken
 
 Full cancellation support via `fable_cancellation.erl`:

docs/docs/beam/features.md

@@ -13,6 +13,17 @@ Beam target is in alpha meaning that breaking changes can happen between minor v
 
 ## Utilities
 
+### `nativeOnly`
+
+`nativeOnly` provides a dummy implementation used when writing bindings to Erlang libraries.
+
+```fs
+[<Import("reverse", "lists")>]
+let reverse : 'a list -> 'a list = nativeOnly
+```
+
+The thrown exception should never be seen as `nativeOnly` calls are replaced by actual Erlang module calls.
+
 ### Automatic case conversion
 
 When targeting Erlang, Fable automatically converts F# camelCase names to Erlang snake_case names.
@@ -57,17 +68,6 @@ maybe_(X) -> X + 1.
 receive_(X) -> X * 2.
 ```
 
-### `nativeOnly`
-
-`nativeOnly` provides a dummy implementation used when writing bindings to Erlang libraries.
-
-```fs
-[<Import("lists", "reverse")>]
-let reverse : 'a list -> 'a list = nativeOnly
-```
-
-The thrown exception should never be seen as `nativeOnly` calls are replaced by actual Erlang module calls.
-
 ## Imports
 
 Fable provides attributes to import Erlang modules and functions.
@@ -289,7 +289,7 @@ Async.RunSynchronously (fetchData ())
 
 - `Async.Parallel` spawns one Erlang process per computation and collects results via message passing
 - `Async.Sleep` uses `timer:sleep`
-- `task { }` is an alias for `async { }` on the Beam target
+- `task { }` is an alias for `async { }` on the Beam target — both compile to the same CPS representation. The hot-start semantics of .NET `Task` are not preserved. Downcasting from `obj` to `Task<T>` or `Async<T>` is not supported
 
 ## MailboxProcessor
 

docs/docs/getting-started/beam.md

@@ -40,8 +40,8 @@ This generates `.erl` files in the output directory (default `./output`).
 Compile the generated Erlang files:
 
 ```bash
-erlc -o output output/*.erl
 erlc -o output/fable_modules/fable-library-beam output/fable_modules/fable-library-beam/*.erl
+erlc -pa output/fable_modules/fable-library-beam -o output output/*.erl
 ```
 
 </li>
@@ -67,3 +67,5 @@ dotnet fable watch --lang beam
 </li>
 
 </ul>
+
+For more details, see [Build and Run](/docs/beam/build-and-run).