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>

src/environment.c

@@ -172,7 +172,7 @@ akerr_ErrorContext *akbasic_environment_stop_waiting(akbasic_Environment *obj, c
 		     "NULL argument in stop_waiting");
     /*
      * The reference ignores `command` and clears unconditionally, which lets an
-     * inner block clear an outer block's wait (TODO.md section 12 item 3). The
+     * inner block clear an outer block's wait (TODO.md §6 item 3). The
      * argument is honoured here only to the extent of walking to the environment
      * that is actually waiting for it -- clearing the wrong one outright would
      * change observable control flow, so the search stops at the first match and

src/runtime.c

@@ -1056,7 +1056,7 @@ akerr_ErrorContext *akbasic_runtime_call_function(akbasic_Runtime *obj, const ch
      * rule.** A multi-line function called at the REPL falls straight past this
      * loop and returns whatever is in the caller's return slot -- zero -- so
      * `PRINT TRIPLE(14)` answers "(UNDEFINED STRING REPRESENTATION FOR 0)" with
-     * no error and no diagnostic. Recorded as TODO.md section 6 item 41.
+     * no error and no diagnostic. Issue #8.
      *
      * Widening it to `mode != AKBASIC_MODE_QUIT` is the obvious fix and is
      * *wrong*: akbasic_runtime_process_line_run() does not advance a REPL-mode

src/runtime_commands.c

@@ -617,7 +617,7 @@ akerr_ErrorContext *akbasic_cmd_dload(akbasic_Runtime *obj, akbasic_ASTLeaf *exp
     /*
      * aksl_fopen does not NULL-check pathname or mode and fopen(NULL, ...) is
      * undefined, so the name is validated here before it is handed over --
-     * deps/libakstdlib/TODO.md 2.2.2.
+     * libakstdlib's UPGRADING.md.
      */
     PASS(errctx, filename_argument(obj, expr, filename, sizeof(filename)));
 

src/runtime_disk.c

@@ -389,7 +389,7 @@ akerr_ErrorContext *akbasic_cmd_directory(akbasic_Runtime *obj, akbasic_ASTLeaf
      * Refused rather than half-built. Listing a directory needs opendir/readdir,
      * which `libakstdlib` does not wrap -- and this project's rule is that a
      * missing capability gets filed upstream rather than worked around here
-     * (MAINTENANCE.md). Filed in deps/libakstdlib/TODO.md.
+     * (MAINTENANCE.md). Filed as libakstdlib issue #10.
      *
      * The alternative was shelling out to `ls`, which a library has no business
      * doing, or calling readdir directly and stepping outside the error

src/symtab.c

@@ -15,7 +15,7 @@
  * Probe for `key`. On success *slot points at either the slot holding the key or
  * the first free slot it could occupy; *found says which. Uses
  * aksl_strhash_djb2 rather than a private hash. That wrapper sign-extends char,
- * so a high-bit byte hashes wrong (deps/libakstdlib/TODO.md 1.6) -- harmless
+ * so a high-bit byte hashes wrong (libakstdlib's UPGRADING.md) -- harmless
  * here because BASIC identifiers are 7-bit ASCII, and it would only ever cost
  * probe efficiency, never correctness, since the key comparison is a strcmp.
  */