diff --git a/docs/web-ui.md b/docs/web-ui.md
index be864b4b..ee2ce321 100644
--- a/docs/web-ui.md
+++ b/docs/web-ui.md
@@ -86,6 +86,20 @@ and, if so, skips the refresh (defers 2s). The operator never has
 the form yanked out from under them mid-type; the update lands as
 soon as they blur.
 
+**Atomic section repaint:** every managed-section renderer goes
+through `paintAtomic(liveRoot, build)`: the builder appends into
+a fresh `DocumentFragment` (off-DOM) and the commit is one
+`replaceChildren` call. The naive `root.innerHTML = ''; root.append(...)`
+shape was visibly flashing empty on every poll cycle — on async
+paths the await yield gave the browser a paint opportunity between
+the clear and the re-append, and on complex builds (many `el()`
+allocations) layout could escape the per-task budget even on the
+synchronous path. The fragment approach keeps the intermediate
+empty state invisible. Builders receive the fragment as their
+`root`, so existing renderer code carries over unchanged; early
+returns inside the builder still commit whatever was appended
+before they returned.
+
 **`<details>` open-state preservation:** any collapsible element
 tagged with `data-restore-key="<stable-key>"` survives the
 refresh. `snapshotOpenDetails()` walks managed sections before
diff --git a/frontend/packages/dashboard/src/tabs.js b/frontend/packages/dashboard/src/tabs.js
index f8f7c892..b0b3ef54 100644
--- a/frontend/packages/dashboard/src/tabs.js
+++ b/frontend/packages/dashboard/src/tabs.js
@@ -1,18 +1,14 @@
 // /index.html entry point: tab renderers + tab routing + refreshState
 // + notification deltas. Reads /api/state on cold load and after every
 // async-form submit; live updates run through `applyXxx` mutation
-// handlers triggered by the dashboard event stream.
+// handlers triggered by the dashboard event stream (subscribed via
+// `openStream` from common.js). See docs/web-ui.md::Shape (shared by
+// both) for the broader contract.
 //
-// #406 step 1: pure helpers + side panel + OS notifications + path
-// linkification moved to `./common.js`.
-// #406 step 2: the flow-only IIFEs (operator inbox, inbox-pill, broker
-// terminal, @-mention composer) moved to `./flow.js`. /flow.html loads
-// `flow.js` as its own bundle entry; this file is loaded only by
-// /index.html.
-// #406 step 3: file renamed from `app.js` → `tabs.js` since it owns
-// the dashboard *tabs* surface only (the FL0W page has its own bundle).
-// Live SSE subscription is wired through `openStream` from common.js
-// (#406 step 3 hookup; see also #408 for stream-side filtering).
+// Pure helpers (DOM, side panel, OS notifications, path linkification)
+// live in `./common.js`; the flow-page surface (operator inbox, broker
+// terminal, @-mention composer) lives in `./flow.js` — `flow.html` and
+// `index.html` each load their own bundle.
 
 import { marked } from 'marked';
 import {
@@ -41,37 +37,16 @@ window.marked = marked;
   const CTX_WARN_TOKENS    = 150_000; // fallback red threshold    (≈ 75% of 200k)
   const CTX_CAUTION_TOKENS = 100_000; // fallback yellow threshold (≈ 50% of 200k)
 
-  // Helpers ($, el, esc, form, fmtAgeSecs) moved to ./common.js (#406).
-
-  // #464 — atomic-swap render helper. Each managed section's render
-  // function used to do `root.innerHTML = ''; root.append(...);` in
-  // sequence; even though both operations sit in the same JS turn,
-  // operators could still see a "blink" on every poll cycle because
-  // (a) on async paths the await yield gave the browser a paint
-  // opportunity, and (b) complex builds with many `el()` allocations
-  // can blow the browser's per-task budget enough for layout to flash
-  // empty before the new children land.
-  //
-  // The fix: build the new content off-DOM into a `DocumentFragment`,
-  // then move it into the live root in a single `replaceChildren`
-  // call. The browser never sees an intermediate empty state. Builder
-  // callbacks receive the fragment as their `root` argument, so each
-  // renderer's existing `root.append(...)` code carries over with
-  // zero internal changes. Early-return inside the builder is fine —
-  // the commit still happens with whatever the builder appended.
+  // Atomic-swap render helper: build into a DocumentFragment off-DOM,
+  // commit with one `replaceChildren`. See docs/web-ui.md::Atomic
+  // section repaint for why (no intermediate empty-state flash on
+  // poll cycles even when the builder allocates a lot of `el()`).
   function paintAtomic(liveRoot, build) {
     const buf = document.createDocumentFragment();
     build(buf);
     liveRoot.replaceChildren(buf);
   }
 
-  // Side panel singleton (Panel) moved to ./common.js (#406).
-
-  // Path linkification + file-preview side panel (openFilePanel,
-  // makePathLink, appendText, appendLinkified) moved to ./common.js (#406).
-
-  // OS notification module (NOTIF) moved to ./common.js (#406).
-
   // Track which items we've already notified about so a re-render
   // doesn't re-fire for the same row. Keyed by stable ids; reset only
   // when the page reloads.