[REMOTE-1326] Link shared sessions to local interactive Oz runs (#9516)

## Description

When Warp starts a shared agent session, we now link that shared session
to the associated Oz run on the server. This enables the Oz run record
to carry the replay session ID, so the session can be surfaced alongside
the run.

**How it works:**
- In `TerminalManager`, when a shared session is created successfully,
the Oz task ID is resolved from the active conversation's `task_id` (set
when the first `StreamInit` response arrives). If found,
`update_agent_task` is called to associate the shared session ID with
the Oz run.
- In the Oz webapp, the "View session" button links to the conversation,
which then redirects to the session if there is one that is active.

**Note on CLI agent runs (`warp agent run`):**
In the CLI agent driver, the shared session is established *before* the
first AI prompt is sent (`wait_for_session_shared()` completes at step 3
of `run_internal`, while the prompt is dispatched at step 5). This means
`active_conversation()` returns `None` at link time and the
session-to-task link is silently skipped for this path. A follow-up will
address linking for CLI agent runs — possible approaches include
deferring the link call until after the first prompt is sent, or
re-introducing a read from `BlocklistAIController.ambient_agent_task_id`
(which the driver sets before sharing begins).

Implements
[REMOTE-1326](https://linear.app/warpdotdev/issue/REMOTE-1326/link-shared-sessions-to-local-interactive-oz-runs).

## Testing

Tested manually by running an in-app Oz agent session, sharing the
terminal, and verifying the resulting Oz task record on the server has
the shared session ID populated.

No automated tests added: the linking path requires a live server
round-trip (shared session creation + `update_agent_task`) and the
happy-path success is silent by design; only failures are logged.

## Server API dependencies

- [ ] Is this change necessary to make the client compatible with a
desired server API breaking change?
- [x] Does this change rely on a new server API?
- [ ] Is this change enabling the use of a server API on client channels
that rely on the production server?

## Agent Mode
- [x] Warp Agent Mode - This PR was created via Warp's AI Agent Mode

## Changelog Entries for Stable

Co-Authored-By: Oz <oz-agent@warp.dev>

---------

Co-authored-by: Oz <oz-agent@warp.dev>

Author: jasonkeung

app/src/terminal/local_tty/terminal_manager.rs

@@ -113,6 +113,7 @@ use super::recorder;
 use super::shell::ShellStarter;
 use super::{event_loop::EventLoop, shell::ShellStarterSource};
 
+use crate::server::server_api::ServerApiProvider;
 #[cfg(unix)]
 use {
     super::terminal_attributes::TerminalAttributesPoller,
@@ -1296,6 +1297,15 @@ impl TerminalManager {
             });
         }
 
+        // Snapshot the conversation the user has selected at click time so the
+        // share is linked to that run, even if selection drifts before the
+        // server confirms session creation.
+        let selected_conversation_id = terminal_view
+            .as_ref(ctx)
+            .ai_context_model()
+            .as_ref(ctx)
+            .selected_conversation_id(ctx);
+
         let active_prompt = if *SessionSettings::as_ref(ctx).honor_ps1 {
             ActivePrompt::PS1
         } else {
@@ -1484,6 +1494,40 @@ impl TerminalManager {
                 if FeatureFlag::AgentSharedSessions.is_enabled() {
                     Self::stream_historical_agent_conversations(&terminal_view, &model, ctx);
                 }
+
+                let session_id_for_link = *session_id;
+
+                // Read task_id lazily so we still pick up a server-assigned
+                // task_id that arrived after the user clicked share.
+                let task_id = selected_conversation_id.and_then(|conversation_id| {
+                    BlocklistAIHistoryModel::as_ref(ctx)
+                        .conversation(&conversation_id)
+                        .and_then(|c| c.task_id())
+                });
+
+                if let Some(task_id) = task_id {
+                    let ai_client = ServerApiProvider::as_ref(ctx).get_ai_client();
+                    terminal_view.update(ctx, |_view, ctx| {
+                        ctx.spawn(
+                            async move {
+                                ai_client
+                                    .update_agent_task(
+                                        task_id,
+                                        None,
+                                        Some(session_id_for_link),
+                                        None,
+                                        None,
+                                    )
+                                    .await
+                            },
+                            move |_view, result, _ctx| {
+                                if let Err(e) = result {
+                                    log::warn!("Failed to link shared session to Oz task: {e}");
+                                }
+                            },
+                        );
+                    });
+                }
             }
             NetworkEvent::FailedToCreateSharedSession {
                 reason,