Repoint the TODO.md citations that no longer resolve

Its own SS0-SS9 structure survived the move to the tracker, so 133 citations
still resolve and are left alone. Thirteen did not.

Six named another repository's TODO.md by a section number: libakstdlib 1.6,
2.2.2 and 2.3, and libakgl's file. Those repositories dropped their numbering
entirely, so each now names UPGRADING.md, an issue, or the tracker.

Three cited 'TODO.md section 12', which has never existed here -- the defect
list is SS6. TODO.md itself caught two others of that class earlier. The
CMakeLists comment carried a stale premise with it: eleven defects
'deliberately reproduced and not yet fixed' stopped being the rule when SS0.1
retired the fidelity constraint.

Four told a reader to record work in TODO.md; the scanner defect is issue #4,
the audio_tables mutation gap is #25, and the UI gaps are libakgl #79 and #80.

Verified: cmake --build build && ctest --test-dir build, 112/112.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Co-Authored-By: Andrew Kesterson <andrew@aklabs.net>

CMakeLists.txt

@@ -3,9 +3,9 @@ cmake_minimum_required(VERSION 3.10)
 # libakgl both use. It flows into the library SOVERSION and nothing else spells
 # a version number.
 #
-# 0.x on purpose: TODO.md section 12 records eleven defects carried over from the
-# Go reference that are deliberately reproduced and not yet fixed, so the
-# language surface is not being promised yet.
+# 0.x on purpose: the language surface is not being promised yet. TODO.md §6
+# records the defects inherited from the Go reference and what became of each;
+# the ones still open are in the issue tracker.
 project(akbasic VERSION 0.1.0 LANGUAGES C)
 
 # Pre-1.0 the ABI may break on a minor bump, so the soname carries MAJOR.MINOR.
@@ -56,7 +56,7 @@ option(AKBASIC_SANITIZE  "Build with ASan + UBSan"                           OFF
 # coverage build collides on the `coverage` target and fails to configure at all.
 # Rename the dependency's on the way past. Remove this once libakerror applies
 # the same CMAKE_SOURCE_DIR test to `coverage` that it already applies to
-# `mutation` -- filed in deps/libakstdlib/TODO.md section 2.3.
+# `mutation` -- filed as libakerror issue #15.
 #
 # **Only one project in a tree may shadow add_test(), and this is that project.**
 # CMake exposes an overridden command as `_name` and chains exactly one level: a
@@ -276,7 +276,7 @@ endif()
 #   AKBASIC_TESTS                must exit 0
 #   AKBASIC_WILL_FAIL_TESTS      abort by design
 #   AKBASIC_KNOWN_FAILING_TESTS  assert the *correct* contract for a defect
-#                                recorded in TODO.md and are expected to fail.
+#                                tracked as issues and are expected to fail.
 #                                When one starts passing CTest reports
 #                                "unexpectedly passed" -- that is the cue to move
 #                                it into AKBASIC_TESTS along with the fix.