fix(web): repair Safari textarea soft-wrap shrink

packages/client/ui-conversation/README.md

@@ -6,7 +6,7 @@ Conversation domain: skeleton (header/tabs/composer/empty state), chat view (gro
 
 Compaction renders as one collapsed row at the checkpoint's flow position without replacing the transcript above it. Automatic compaction uses the context-compacted title. Every completed marker with a loaded `compaction/summary` event shows the replaced-item and estimated-token counts and discloses the summary on click. Manual `/compact` starts as a running `compact` row; on successful settlement its explicit summary-event reference folds that command into the checkpoint row under the same React key. A completed checkpoint keeps the context-compaction icon at rest and replaces it with the collapsed or expanded disclosure only on hover or keyboard focus. Input rejection, no compactable history, cancellation, and failure retain the generic command row and its handler-authored text. Pairing never depends on adjacency because durable context may be injected while compaction is running. The framed checkpoint payload is model-facing and never renders; when the cited `compaction/summary` event is outside the loaded window, the checkpoint remains visible but non-expandable.
 
-The resident conversation shell survives no-session and session transitions. Without a current session it locks message actions and presents the whole dashed composer card as a trigger for the root-scoped `conversation.hero.workspace` Workspace picker; the textarea remains read-only and keyboard-accessible. Selecting a Workspace connects or reuses its Host-owned blank session and opens that session without replacing the shell. The root always owns the same scrollport and Hero/composer subtree; separate strict-session header and body outlets fill their regions when the first Session arrives, so the Workspace picker, scroll body, composer seat, and textarea retain their React and DOM identity. Blank sessions render the same composer body as active sessions, while the InputHub carries drafts across Workspace switches and mirrors them into the session store. In the active phase the session header shows only the current session title and view tabs as ordinary column chrome; fork lineage remains session data and is not projected into the header. Beneath it the scrollport (`data-conversation-scroll`) holds the flowing views and the sticky composer stack (stats dock + input docks + bar). That scrollport reserves its scrollbar gutter unconditionally, and a view opting into a composer overlay leaves it a scroll container, so the input card keeps one horizontal position whether or not the transcript scrolls and whichever view tab is shown ([decision](../../../.agents/notes/implemented/bug-fix/2026-08-04-composer-tab-gutter-reservation.md)). Wheel over the textarea chains: the capped draft scrolls locally until its edge, then forwards to that host.
+The resident conversation shell survives no-session and session transitions. Without a current session it locks message actions and presents the whole dashed composer card as a trigger for the root-scoped `conversation.hero.workspace` Workspace picker; the textarea remains read-only and keyboard-accessible. Selecting a Workspace connects or reuses its Host-owned blank session and opens that session without replacing the shell. The root always owns the same scrollport and Hero/composer subtree; separate strict-session header and body outlets fill their regions when the first Session arrives, so the Workspace picker, scroll body, composer seat, and textarea retain their React and DOM identity. Blank sessions render the same composer body as active sessions, while the InputHub carries drafts across Workspace switches and mirrors them into the session store. In the active phase the session header shows only the current session title and view tabs as ordinary column chrome; fork lineage remains session data and is not projected into the header. Beneath it the scrollport (`data-conversation-scroll`) holds the flowing views and the sticky composer stack (stats dock + input docks + bar). That scrollport reserves its scrollbar gutter unconditionally, and a view opting into a composer overlay leaves it a scroll container, so the input card keeps one horizontal position whether or not the transcript scrolls and whichever view tab is shown ([decision](../../../.agents/notes/implemented/bug-fix/2026-08-04-composer-tab-gutter-reservation.md)). Wheel over the textarea chains: the capped draft scrolls locally until its edge, then forwards to that host. Safari alone receives a pre-paint recovery when a native edit shortens the draft and leaves stale soft-wrap overflow; draft growth, programmatic updates, and other browsers never read layout for that recovery ([decision](../../../.agents/notes/implemented/bug-fix/2026-08-13-safari-textarea-soft-wrap-reflow.md)).
 
 Another plugin can make one session's composer inert through `ctx.conversation.blocks`: it sets a block carrying its own localized reason, and the bar renders the same disabled textarea with that reason as the placeholder — the no-workspace posture, reused. The push direction is the constraint, not a preference: the plugins that know a session cannot send (ui-model-selection, when no adapter serves its route) already depend on this package, so this package cannot read them. The model seat is the one control a block leaves live — every block this contract has is cleared by choosing a model, so locking it too would leave the composer asking for the only thing it prevents. A block is an affordance only; the Host refuses a prompt it cannot route regardless of what any client disables. The no-workspace state wins when both hold, because picking a workspace is the earlier prerequisite.