salience: client-side pad expansion, drop AppendImage

Mirrors the vLLM-side rewrite. AppendImage is gone; images now
ride along on Generate via a parallel `images` list.

- Productionize `qwen3_image_token_count` (was test-only). Image
  leaf computes its IMAGE_PAD count eagerly at construction from
  height/width; `token_count` is no longer "0 until the server
  tells us."
- WireChunk shrinks to a single `Tokens(Vec<u32>)` variant — vision
  blocks live inline in the token stream.
- `wire_chunks` now returns `(Vec<WireChunk>, Vec<WireImage>)`.
  `WireImage` carries `pad_start` / `pad_end` (absolute positions
  in the full walk) alongside bytes + mime.
- `assemble_prompt` returns `(chunks, images, match_upto)`.
- `stream_session_mm` / `run_session_generate` take the parallel
  images list, filter to those past `match_upto`, and pass them
  in `GenerateRequest.images` as `pb::ImageAttachment` entries.
- Drop `SessionHandle::append_image`,
  `ContextState::commit_image_token_counts`,
  `StreamToken::ImageAppended`, the WireChunk::Image branch in
  `learn.rs`, and the now-empty `prompt_to_chunks` helper.
- Add 'v' toggle on the conscious-screen tree to render token-id
  vectors in place of text content (debug-aid: lets us see what
  the server actually has when output is suspicious).
- Comment out the subconscious-trigger spawn loop — Kent had this
  disabled before; it had crept back into running.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/user/widgets.rs

@@ -8,11 +8,18 @@ use ratatui::{
 };
 use crate::agent::context::{AstNode, Ast, NodeBody};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct SectionView {
     pub name: String,
     pub tokens: usize,
     pub content: String,
+    /// Token-id stream for this subtree, displayed in place of
+    /// `content` when the tree's show-tokens mode is on. Populated
+    /// from `leaf.token_ids()` / `node.token_ids()` for views built
+    /// from the AST; empty for views that don't have a corresponding
+    /// AST node (subconscious entries, etc.), in which case the
+    /// token view falls back to the text content.
+    pub token_ids: Vec<u32>,
     pub children: Vec<SectionView>,
     /// Extra status text shown after the token count.
     pub status: String,
@@ -32,6 +39,7 @@ fn node_to_view(node: &AstNode) -> SectionView {
                 name,
                 tokens: node.tokens(),
                 content: leaf.body().text().to_string(),
+                token_ids: leaf.token_ids().to_vec(),
                 children: Vec::new(),
                 status,
             }
@@ -44,6 +52,7 @@ fn node_to_view(node: &AstNode) -> SectionView {
                 name: node.label(),
                 tokens: node.tokens(),
                 content: String::new(),
+                token_ids: node.token_ids(),
                 children: child_views,
                 status: String::new(),
             }
@@ -54,10 +63,12 @@ fn node_to_view(node: &AstNode) -> SectionView {
 pub fn section_to_view(name: &str, nodes: &[AstNode]) -> SectionView {
     let children: Vec<SectionView> = nodes.iter().map(|n| node_to_view(n)).collect();
     let total_tokens: usize = nodes.iter().map(|n| n.tokens()).sum();
+    let token_ids: Vec<u32> = nodes.iter().flat_map(|n| n.token_ids()).collect();
     SectionView {
         name: name.to_string(),
         tokens: total_tokens,
         content: String::new(),
+        token_ids,
         children,
         status: String::new(),
     }
@@ -104,7 +115,7 @@ pub fn format_ts_age(ts: i64) -> String {
 /// Key legend for SectionTree panes.
 pub fn tree_legend() -> Line<'static> {
     Line::styled(
-        " ↑↓:nav  →/Enter:expand  ←:collapse  e:expand all  c:collapse all  PgUp/Dn  Home/End ",
+        " ↑↓:nav  →/Enter:expand  ←:collapse  e:expand  c:collapse  v:toggle tokens/text  PgUp/Dn ",
         Style::default().fg(Color::DarkGray),
     )
 }
@@ -185,11 +196,19 @@ pub struct SectionTree {
     pub selected: Option<usize>,
     pub expanded: std::collections::HashSet<usize>,
     pub scroll: super::scroll_pane::ScrollPaneState,
+    /// When true, render `token_ids` as space-separated IDs in place
+    /// of `content` in expanded panels. Toggled with 'v'.
+    pub show_tokens: bool,
 }
 
 impl SectionTree {
     pub fn new() -> Self {
-        Self { selected: None, expanded: std::collections::HashSet::new(), scroll: super::scroll_pane::ScrollPaneState::new() }
+        Self {
+            selected: None,
+            expanded: std::collections::HashSet::new(),
+            scroll: super::scroll_pane::ScrollPaneState::new(),
+            show_tokens: false,
+        }
     }
 
     fn total_nodes(&self, sections: &[SectionView]) -> usize {
@@ -264,6 +283,9 @@ impl SectionTree {
             KeyCode::Char('c') => {
                 self.expanded.clear();
             }
+            KeyCode::Char('v') => {
+                self.show_tokens = !self.show_tokens;
+            }
             _ => {}
         }
         self.scroll_to_selected(height);
@@ -326,7 +348,12 @@ impl SectionTree {
                 }
             } else if has_content {
                 let content_indent = format!("{}    │ ", "  ".repeat(depth + 1));
-                let content_lines: Vec<&str> = section.content.lines().collect();
+                let body = if self.show_tokens && !section.token_ids.is_empty() {
+                    format_token_ids_wrapped(&section.token_ids)
+                } else {
+                    section.content.clone()
+                };
+                let content_lines: Vec<&str> = body.lines().collect();
                 let show = content_lines.len().min(50);
                 for line in &content_lines[..show] {
                     lines.push(Line::styled(
@@ -344,3 +371,16 @@ impl SectionTree {
         }
     }
 }
+
+/// Format token IDs for the content panel: space-separated, wrapped
+/// at 12 ids per line so they fit comfortably in a pane.
+fn format_token_ids_wrapped(ids: &[u32]) -> String {
+    let mut out = String::new();
+    for (i, id) in ids.iter().enumerate() {
+        if i > 0 {
+            if i % 12 == 0 { out.push('\n'); } else { out.push(' '); }
+        }
+        out.push_str(&id.to_string());
+    }
+    out
+}