fix: the draft picker fills the content column, not the window

The overlay is absolute inset-0 — it resolves against its nearest
positioned ancestor. Mounted at the NewSession root it spanned the
whole window, over the sidebar and the traffic lights. It now hosts
inside the draft content column's relative container (the overlay
slot on DraftShell) — the same confinement the graph view gives it:
right of the sidebar, under the top bar, inside the session's section.

components/new-session.tsx

@@ -81,6 +81,7 @@ export function DraftShell({
 	picks = [],
 	onOpenPicker,
 	onClearPicks,
+	overlay,
 }: {
 	busy: boolean;
 	text: string;
@@ -102,6 +103,11 @@ export function DraftShell({
 	picks?: DraftPick[];
 	onOpenPicker?: () => void;
 	onClearPicks?: () => void;
+	/** THE PICKER SLOT (owner round 10b): the chain-table overlay hosts
+	 *  INSIDE the content column's relative container — the same law as
+	 *  the graph view (the overlay fills its column, never the sidebar).
+	 *  Passed as a node so the pick state stays in NewSession. */
+	overlay?: ReactNode;
 }) {
 	// Voice dictation (STT wave, 2026-09-17): finals append at the end of the
 	// draft text (via the parent's onChange — the truth lives there); the
@@ -228,6 +234,7 @@ export function DraftShell({
 							</div>
 						</div>
 					</div>
+					{overlay}
 				</div>
 			</div>
 		</div>
@@ -327,6 +334,31 @@ export function NewSession({ initialConfigured, mode = "teach" }: { initialConfi
 				picks={picks}
 				onOpenPicker={openPicker}
 				onClearPicks={() => applyPicks([])}
+				overlay={
+					// THE PICKER (owner round 10b): hosted INSIDE the content
+					// column — absolute inset-0 resolves to the column's relative
+					// container, the same confinement the graph view gives it;
+					// never over the sidebar or the traffic lights.
+					<ChainTableOverlay
+						open={pickerOpen}
+						nodes={snapshot?.propositions ?? []}
+						chains={snapshot?.chains ?? []}
+						sessions={snapshot?.sessions ?? {}}
+						fileSources={snapshot?.fileSources ?? {}}
+						onClose={() => setPickerOpen(false)}
+						selectMode
+						controlledSelection={new Set(picks.map((p) => p.id))}
+						onSelectionChange={(ids) => {
+							const byId = new Map((snapshot?.propositions ?? []).map((n) => [n.id, n]));
+							const next: DraftPick[] = [];
+							for (const id of ids) {
+								const n = byId.get(id);
+								if (n) next.push({ id: n.id, name: n.name, statement: n.statement });
+							}
+							applyPicks(next);
+						}}
+					/>
+				}
 				setupCta={
 					zeroKeys ? (
 						<ZeroKeysPill onOpen={() => setSetupOpen(true)} />
@@ -346,29 +378,6 @@ export function NewSession({ initialConfigured, mode = "teach" }: { initialConfi
 					)
 				}
 			/>
-			{/* THE PICKER (owner round 10): the standalone chain table over
-			    fetched snapshot data — the same select-mode overlay the home
-			    graph hosts, no graph canvas needed behind it. Controlled
-			    selection: every check/clear reports up live; Done closes. */}
-			<ChainTableOverlay
-				open={pickerOpen}
-				nodes={snapshot?.propositions ?? []}
-				chains={snapshot?.chains ?? []}
-				sessions={snapshot?.sessions ?? {}}
-				fileSources={snapshot?.fileSources ?? {}}
-				onClose={() => setPickerOpen(false)}
-				selectMode
-				controlledSelection={new Set(picks.map((p) => p.id))}
-				onSelectionChange={(ids) => {
-					const byId = new Map((snapshot?.propositions ?? []).map((n) => [n.id, n]));
-					const next: DraftPick[] = [];
-					for (const id of ids) {
-						const n = byId.get(id);
-						if (n) next.push({ id: n.id, name: n.name, statement: n.statement });
-					}
-					applyPicks(next);
-				}}
-			/>
 			{/* First-run setup: the send interception's landing surface — stage
 			    1 is the self-contained first-key screen (zero-keys wave). */}
 			<SetupDialog