Every example in the docs is verified to compile + run at -std=c++14 (GCC 14.3
locally in Docker, incl. SDL2 for sdl2.cpp; arduino compiles to an empty main
without Arduino.h) and on Compiler Explorer (GCC 14.2). A 'Run on Compiler
Explorer' link is added beside each ![CPP] embed across examples.md, tutorial.md,
user_guide.md, index.md and overview.md (65 links total).

Since Boost.SML is not a Compiler Explorer library, each link inlines sml.hpp
(and dispatch_table.hpp where used); BOOST_SML_* config macros are hoisted above
the header so they still apply (e.g. data.cpp). The error/* examples get
compile-only links that show their intended diagnostic.

Also fixes broken doc links:
- user_guide.md: example/action_guards.cpp -> example/actions_guards.cpp (typo)
- user_guide.md: example/errors/not_*.cpp -> test/ft/errors/not_*.cpp (wrong path)

Adds doc/scripts/gen_godbolt_links.sh to regenerate the links reproducibly.

The in-page 'Compile & Run' buttons POSTed to http://melpon.org/wandbox
(plain HTTP -> mixed-content blocked on the HTTPS site, and a dead host).

- Repoint to https://wandbox.org/api/compile.json (alive; sends
  Access-Control-Allow-Origin: * so the cross-origin XHR works).
- Drop the now-invalid 'boost-1.60' compile option (it makes the API reject
  the request; SML has no Boost dependency anyway).
- Supply boost/sml/utility/dispatch_table.hpp alongside boost/sml.hpp so the
  dispatch_table and sdl2 examples also run.
- Update the 'Powered by Wandbox' footer link to https://wandbox.org.

Verified end-to-end against the live API at -std=c++14 (clang-head):
hello_world, composite, data, transitions, dispatch_table and sdl2 all
return status 0 (sdl2 prints its expected output).

- Run doc/scripts/update_readme_toc.py so the README's auto-generated table of
  contents reflects the new FAQ 'Limitations' section and the '[Unreleased] -
  since 1.1.13' CHANGELOG entry.
- Adjust faq.md heading levels (page title -> h1) so the generator does not emit
  a redundant 'FAQ' child entry under the FAQ link.

Cut the next release. Minor bump (not patch): this release adds new public API
(sm::flush_queue, sml::clear_defer, sml::deps<Ts...>) and changes observable
behavior (empty-SM sizeof under boost-ext#249), so it is 1.2.0 per semver.

- BOOST_SML_VERSION 1'1'13 -> 1'2'0; inline namespace v1_1_13 -> v1_2_0
- CMakeLists package version 1.1.13 -> 1.2.0
- CHANGELOG: finalize the entry as [1.2.0] - 2026-06-01 (compare link -> v1.2.0)
- README: regenerate documentation TOC for the 1.2.0 changelog entry

The v1.1.13 -> v1.2.0 inline-namespace rename (v1_1_13 -> v1_2_0) shortened the
namespace string by one character. get_type_name() skips a hardcoded prefix
length into __FUNCSIG__/__PRETTY_FUNCTION__, and that prefix includes the inline
namespace on MSVC/GCC/IAR (clang elides it). The stale offsets made
get_type_name<int>() return the wrong substring, failing test_type_traits (all
compilers) and test_policies_logging (GCC).

Adjust the affected offsets by -1: MSVC 65->64, GCC 69->68, IAR 72->71; clang
(50/63) is namespace-length-independent and unchanged. GCC 68 matches the
pre-1.1.10 value for a 6-char namespace.

Verified: full ctest suite 68/68 on GCC (C++17); MSVC type_traits passes under
msvc-wine (and fails at offset 65, confirming 64). Added a comment so the offsets
are re-tuned on future namespace-length changes.

Fixes CI on PR boost-ext#708 (ubuntu g++, windows MSVC).

boost-ext#706 (sml::make_action<Deps...>, issue boost-ext#629) is now merged into master, so this
rebases onto it and documents it:
- CHANGELOG: add make_action to the 1.2.0 additions
- user_guide: new 'make_action [utility]' reference section with a verified run-link
- tutorial: note make_action in the guards/actions section
- README: regenerate TOC (adds the make_action entry)

Regenerate every Compiler Explorer link against the v1.2.0 header (inline namespace
v1_2_0) and re-verify each compiles + runs at -std=c++14 on godbolt (arduino c++20);
replace the stale v1_1_13-era links across examples/tutorial/user_guide/index/overview.

Also fix a bug in gen_godbolt_links.sh exposed during regeneration: the config-macro
hoist strip (#define BOOST_SML*) was applied to dispatch_table.hpp too, deleting its
deliberate re-#define of BOOST_SML_DETAIL_REQUIRES (sml.hpp #undef's it before that
point) and breaking the dispatch_table/sdl2 links. Strip only the sml.hpp include
from dispatch_table.hpp; keep its #define/#undef. The standalone make_action link is
now preserved across --insert re-runs.