chore: comments say what the code does, not which task produced it

A comment that reads "MUST stay in lockstep with TryGetActiveCrossfade (K8)"
helps nobody outside the plan that used to have a K8 in it, and the plans are
not in this repo. Same for "Spec FR-4", "plan §B.2", "Sub-Task 4.4" and the
F/R/M/A/S round codes scattered through the style engine and the self-tests.

Personal names go too. "tester feedback from Jin (v1.4.7)" and "Flo decision
2026-06-15" carry the reason fine without naming anyone -- the version and the
reason are the parts a reader can act on, and a public repo should not need a
cast list to be read.

The rule applied throughout: keep the why, drop the reference. Version numbers
stay, since those resolve through the changelog. 77 files.

ChunkUtil also carried 281 lines of commented-out code -- an older ToChunks
variant and two helpers with no callers, inherited and never removed. Deleted;
git remembers them.

HellionChat/Services/TellRouterService.cs

@@ -5,7 +5,7 @@ using Microsoft.Extensions.Logging;
 namespace HellionChat.Services;
 
 // Routes an incoming tell to the configured TellAutoOpenMode (Off/Sidebar/
-// TopTab/Popout). Decoupled from AutoTellTabsService (Flo decision 2026-06-15):
+// TopTab/Popout). Deliberately decoupled from AutoTellTabsService:
 // that service owns tab CREATION + lifecycle; this only REVEALS/pops the tab it
 // finds. Popout guards on pool.IsOpen so it never double-pops a tab the
 // AutoTellTabsOpenAsPopout path already opened. Subscribes to the resolved