Per mara's guidance on hyperhive#3901 (target ~15% comment density
overall, less where obvious, more where not; prefer docs for
abstract/general topics; don't restate facts in multiple places;
don't document history).
tabs.js: removed 4 pure "X now lives in Y" / "moved to Z" historical
asides (the underlying facts are already documented in
docs/web-ui/dashboard.md, not lost by removing the floating in-code
aside) and merged one comment block that had drifted into restating
the same fact twice (one ticker feeding two live displays, documented
as if it were two separate tickers).
swarm.js: cut a comment narrating the removal history of two features
that no longer exist in the code (a per-agent queued-badge and a
client-side jobq tally), keeping only the design constraint still in
force (why the jobq-derived state here is deliberately narrow); cut a
comment documenting a removed CSS class's history down to a statement
of the current class's purpose; cut a comment restating the
jobq-rollup rendering rationale already stated once, above, down to a
one-line pointer; trimmed a "legacy flat layout is bit-identical"
history clause down to what the depth-0 case actually renders.