Shrink a photo to what the provider takes, and put it in its own bubble

Sending an image was broken in the way that is hardest to see from the
phone: a camera photo is twelve megapixels and several megabytes, the Claude
API resizes anything past 1568px on its long edge before looking at it and
refuses far larger outright, so the picture was uploaded whole over the
tunnel to be thrown away or rejected at the other end.

Shrunk on the phone, to a limit the server states. Which number it is comes
from the provider's *kind* -- `DriverKind::max_image_edge`, reported on the
session row -- because that is where a provider's requirements are known,
and a phone carrying its own copy of them would be a second place to update
when one changes. `None` where nothing cares, rather than a large number:
"no limit" and "a limit that happens to be big" are different answers and
only one of them stays true. Doing it before the upload rather than after is
the point -- the expensive part on a phone is the tunnel, not the decode --
and an image already inside the limit is uploaded byte for byte rather than
being round-tripped through JPEG for nothing.

EXIF orientation is applied while scaling. The camera writes which way up
the picture is into a tag rather than into the pixels, and re-encoding drops
it, so a portrait photo would have arrived at the model on its side with
nothing anywhere saying so.

**What is attached is now visible before it is sent**, in a row directly
above the box it will be sent from: the count on the "+" button said how
many and never which, so the only way to find out what you had picked was to
send it. It scrolls sideways rather than shrinking, and tapping one takes it
back off -- an image picked by mistake could otherwise only be dealt with by
sending it. The tile is outlined as well as filled, because most of what
gets attached here is a screenshot of a dark app and a cropped one is
near-black: without an edge the only thing on screen saying an image was
attached was the cross drawn on top of nothing.

**And the picture is inside the bubble that sent it.** Attachments used to
be their own `Image` events emitted just before the message, which drew
somebody's screenshot as a row floating above the bubble and left the phone
deciding from adjacency alone which message an image belonged to -- a thing
the sender knew and could simply say. `UserMessage`, `MessageQueued` and
`MessageTaken` carry the refs now, so a waiting message keeps its picture
for as long as the turn runs, and a replay puts it back in the same place.

Verified on a real claude-cli session rather than an echo one, since the
limit only exists for that kind: a 3000x4000 image arrived as 1176x1568
JPEG -- long edge exactly the limit, aspect ratio intact -- and haiku
answered "AI Sessions displays idle Photo", which is what the picture was.
No error, and the transcript records the message with `images` on it.

server/src/session/mod.rs

@@ -146,6 +146,13 @@ pub struct SessionInfo {
     /// Every token this session has spent, so a phone showing a total does
     /// not have to add up a transcript it only holds part of.
     pub total_tokens: u64,
+    /// The longest edge an image should have by the time it gets here, or
+    /// absent where this provider has no limit -- see
+    /// [`DriverKind::max_image_edge`]. Absent rather than a large number,
+    /// because "no limit" and "a limit that happens to be big" are different
+    /// answers and only one of them stays true.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub max_image_edge: Option<u32>,
     /// Whether this session announces itself -- reported for the same
     /// reason `permission_mode` is: a switch that guesses its own position
     /// is how you turn something off while believing you are reading it.
@@ -290,17 +297,11 @@ impl LiveSession {
     /// turn it waits, and writing it down on the way past would put it
     /// above output that happened before the session ever saw it.
     pub fn send_message(&self, text: String, images: Vec<ImageRef>) {
-        // Attachments are the exception, recorded on the way past: they
-        // are uploaded whether or not the message waits, and the phone
-        // fetches them by the same ref the files route serves. So a queued
-        // message's picture appears a little before its text.
-        for image in &images {
-            let _ = self.sink.send(Event::Image {
-                image: image.clone(),
-                // A person's own attachment belongs to no tool call.
-                about: None,
-            });
-        }
+        // The attachments ride *on* the message rather than as `Image`
+        // events emitted just before it. They used to be the latter, which
+        // drew a person's screenshot as a row floating above the bubble
+        // that sent it, and left the phone inferring from adjacency which
+        // message an image went with -- a thing the sender already knew.
         self.driver.send_user_message(text, images);
     }
 
@@ -370,7 +371,13 @@ impl LiveSession {
 
     /// `setup_name` is passed in rather than stored: only the manager
     /// holds the config, and the label can change under a running session.
-    fn info(&self, setup_name: &str, imported: bool, keeps_own_transcript: bool) -> SessionInfo {
+    /// `kind` rather than the facts derived from it: two of this row's
+    /// fields are answers about the provider's *kind*, and passing them
+    /// separately meant every caller deriving each one and a third arriving
+    /// as a third parameter. `None` where the provider has been edited away,
+    /// which is a session that cannot run -- so both answers are the
+    /// cautious one rather than a guess.
+    fn info(&self, setup_name: &str, imported: bool, kind: Option<DriverKind>) -> SessionInfo {
         SessionInfo {
             id: self.meta.id.clone(),
             provider: self.meta.provider.clone(),
@@ -381,8 +388,9 @@ impl LiveSession {
             permission_mode: self.shared.permission_mode.lock().unwrap().clone(),
             total_tokens: *self.shared.total_tokens.lock().unwrap(),
             notify: *self.shared.notify.lock().unwrap(),
+            max_image_edge: kind.and_then(DriverKind::max_image_edge),
             imported,
-            keeps_own_transcript,
+            keeps_own_transcript: kind.is_some_and(DriverKind::keeps_own_transcript),
             cwd: self.meta.cwd.clone(),
             status: *self.shared.status.lock().unwrap(),
             last_activity: *self.shared.last_activity.lock().unwrap(),
@@ -706,7 +714,7 @@ impl SessionManager {
                 Some(session) => session.info(
                     label_of(&inner.config, &meta.setup),
                     import::read_cursor(&self.data_dir.join(&meta.id)).is_some(),
-                    keeps_own_transcript(&inner.config, &meta.setup, &meta.provider),
+                    kind_of(&inner.config, &meta.setup, &meta.provider),
                 ),
                 None => SessionInfo {
                     id: meta.id.clone(),
@@ -717,6 +725,8 @@ impl SessionManager {
                     model: meta.model.clone(),
                     permission_mode: meta.permission_mode.clone(),
                     total_tokens: 0,
+                    max_image_edge: kind_of(&inner.config, &meta.setup, &meta.provider)
+                        .and_then(DriverKind::max_image_edge),
                     notify: meta.notify,
                     imported: import::read_cursor(&self.data_dir.join(&meta.id)).is_some(),
                     keeps_own_transcript: keeps_own_transcript(
@@ -853,7 +863,7 @@ impl SessionManager {
         let info = session.info(
             &setup.name,
             import::read_cursor(&self.data_dir.join(&id)).is_some(),
-            provider.kind.keeps_own_transcript(),
+            Some(provider.kind),
         );
         inner.live.insert(id, session);
         Ok(info)
@@ -1057,10 +1067,17 @@ fn label_of<'a>(config: &'a Config, id: &'a str) -> &'a str {
 /// "this can be brought back" on no evidence is the answer that loses
 /// somebody's conversation.
 fn keeps_own_transcript(config: &Config, setup: &str, provider: &str) -> bool {
+    kind_of(config, setup, provider).is_some_and(DriverKind::keeps_own_transcript)
+}
+
+/// What a session's provider is, for the questions answered by its *kind*
+/// rather than by its name. `None` for a provider that has been edited away,
+/// which is a session that cannot run at all.
+fn kind_of(config: &Config, setup: &str, provider: &str) -> Option<DriverKind> {
     config
         .setup(setup)
         .and_then(|setup| setup.providers.iter().find(|it| it.name == provider))
-        .is_some_and(|provider| provider.kind.keeps_own_transcript())
+        .map(|provider| provider.kind)
 }
 
 /// Names for a failure message: what there is, so the reader can see what
@@ -1363,7 +1380,7 @@ async fn pump(
         // message here rather than being carried alongside it. One rule
         // for where a user's message sits: where the session read it.
         let event = match event {
-            Event::MessageTaken { id, text } => Event::UserMessage { id, text },
+            Event::MessageTaken { id, text, images } => Event::UserMessage { id, text, images },
             // The running total is the pump's to keep, for the reason the
             // field gives: a driver knows what its own turn cost and
             // nothing else does. Added here rather than at each driver so
@@ -1606,7 +1623,7 @@ mod tests {
         assert_eq!(first.session_id, info.id);
         // The title travels with it, because the phone may have no screen
         // open to look one up on.
-        assert_eq!(first.title, session.info("m", false, false).title);
+        assert_eq!(first.title, session.info("m", false, None).title);
 
         manager.set_session_notify(&info.id, false).expect("off");
         // Subscribed before the message, or the turn can finish in the gap