report global cycle endpoints

TODO.md

@@ -1,6 +1,10 @@
-# "quick" / "easy" fixes
+# general todos
 
-- for global initialization cycles, report also starting and ending lines
+- sum-type ABI/layout polish
+  - consider dynamic tag-width shrinking after the fixed-`u16` ABI has real pressure
+  - consider all-void channel collapse after fallible channels are otherwise stable
+  - define cross-module/global-id ABI determinism before multi-module builds depend on it
+  - keep backed/C enum composition and must-consume fallible linting as later policy work
 
 # milestones
 
@@ -590,17 +594,9 @@
     spelling for void-payload variants
   - named fallible signatures can use inline unbacked enum and `union(enum)` error types
     after `!`
-  - qualified same-name disambiguation remains deferred; existing ambiguous fallible return
-    diagnostics cover the current surface
 
 23.7. anonymous struct payloads and keyed payload sugar
 
-23.8. sum-type ABI/layout polish
-  - consider dynamic tag-width shrinking after the fixed-`u16` ABI has real pressure
-  - consider all-void channel collapse after fallible channels are otherwise stable
-  - define cross-module/global-id ABI determinism before multi-module builds depend on it
-  - keep backed/C enum composition and must-consume fallible linting as later policy work
-
 24. dynamic heap allocation
   - see below for direction
   - notes below are too big in scope for a first pass and the language is not mature enough to support it yet