Fully support all mention kinds (#36134)

Feature parity with the agent1 @mention kinds:
- File
- Symbols
- Selections
- Threads
- Rules
- Fetch


Release Notes:

- N/A

---------

Co-authored-by: Cole Miller <cole@zed.dev>

crates/agent_ui/src/context_picker.rs

@@ -1,15 +1,16 @@
 mod completion_provider;
-mod fetch_context_picker;
+pub(crate) mod fetch_context_picker;
 pub(crate) mod file_context_picker;
-mod rules_context_picker;
-mod symbol_context_picker;
-mod thread_context_picker;
+pub(crate) mod rules_context_picker;
+pub(crate) mod symbol_context_picker;
+pub(crate) mod thread_context_picker;
 
 use std::ops::Range;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
 use anyhow::{Result, anyhow};
+use collections::HashSet;
 pub use completion_provider::ContextPickerCompletionProvider;
 use editor::display_map::{Crease, CreaseId, CreaseMetadata, FoldId};
 use editor::{Anchor, AnchorRangeExt as _, Editor, ExcerptId, FoldPlaceholder, ToOffset};
@@ -45,7 +46,7 @@ use agent::{
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum ContextPickerEntry {
+pub(crate) enum ContextPickerEntry {
     Mode(ContextPickerMode),
     Action(ContextPickerAction),
 }
@@ -74,7 +75,7 @@ impl ContextPickerEntry {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum ContextPickerMode {
+pub(crate) enum ContextPickerMode {
     File,
     Symbol,
     Fetch,
@@ -83,7 +84,7 @@ enum ContextPickerMode {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum ContextPickerAction {
+pub(crate) enum ContextPickerAction {
     AddSelections,
 }
 
@@ -531,7 +532,7 @@ impl ContextPicker {
             return vec![];
         };
 
-        recent_context_picker_entries(
+        recent_context_picker_entries_with_store(
             context_store,
             self.thread_store.clone(),
             self.text_thread_store.clone(),
@@ -585,7 +586,8 @@ impl Render for ContextPicker {
             })
     }
 }
-enum RecentEntry {
+
+pub(crate) enum RecentEntry {
     File {
         project_path: ProjectPath,
         path_prefix: Arc<str>,
@@ -593,7 +595,7 @@ enum RecentEntry {
     Thread(ThreadContextEntry),
 }
 
-fn available_context_picker_entries(
+pub(crate) fn available_context_picker_entries(
     prompt_store: &Option<Entity<PromptStore>>,
     thread_store: &Option<WeakEntity<ThreadStore>>,
     workspace: &Entity<Workspace>,
@@ -630,24 +632,56 @@ fn available_context_picker_entries(
     entries
 }
 
-fn recent_context_picker_entries(
+fn recent_context_picker_entries_with_store(
     context_store: Entity<ContextStore>,
     thread_store: Option<WeakEntity<ThreadStore>>,
     text_thread_store: Option<WeakEntity<TextThreadStore>>,
     workspace: Entity<Workspace>,
     exclude_path: Option<ProjectPath>,
     cx: &App,
+) -> Vec<RecentEntry> {
+    let project = workspace.read(cx).project();
+
+    let mut exclude_paths = context_store.read(cx).file_paths(cx);
+    exclude_paths.extend(exclude_path);
+
+    let exclude_paths = exclude_paths
+        .into_iter()
+        .filter_map(|project_path| project.read(cx).absolute_path(&project_path, cx))
+        .collect();
+
+    let exclude_threads = context_store.read(cx).thread_ids();
+
+    recent_context_picker_entries(
+        thread_store,
+        text_thread_store,
+        workspace,
+        &exclude_paths,
+        exclude_threads,
+        cx,
+    )
+}
+
+pub(crate) fn recent_context_picker_entries(
+    thread_store: Option<WeakEntity<ThreadStore>>,
+    text_thread_store: Option<WeakEntity<TextThreadStore>>,
+    workspace: Entity<Workspace>,
+    exclude_paths: &HashSet<PathBuf>,
+    exclude_threads: &HashSet<ThreadId>,
+    cx: &App,
 ) -> Vec<RecentEntry> {
     let mut recent = Vec::with_capacity(6);
-    let mut current_files = context_store.read(cx).file_paths(cx);
-    current_files.extend(exclude_path);
     let workspace = workspace.read(cx);
     let project = workspace.project().read(cx);
 
     recent.extend(
         workspace
             .recent_navigation_history_iter(cx)
-            .filter(|(path, _)| !current_files.contains(path))
+            .filter(|(_, abs_path)| {
+                abs_path
+                    .as_ref()
+                    .map_or(true, |path| !exclude_paths.contains(path.as_path()))
+            })
             .take(4)
             .filter_map(|(project_path, _)| {
                 project
@@ -659,8 +693,6 @@ fn recent_context_picker_entries(
             }),
     );
 
-    let current_threads = context_store.read(cx).thread_ids();
-
     let active_thread_id = workspace
         .panel::<AgentPanel>(cx)
         .and_then(|panel| Some(panel.read(cx).active_thread(cx)?.read(cx).id()));
@@ -672,7 +704,7 @@ fn recent_context_picker_entries(
         let mut threads = unordered_thread_entries(thread_store, text_thread_store, cx)
             .filter(|(_, thread)| match thread {
                 ThreadContextEntry::Thread { id, .. } => {
-                    Some(id) != active_thread_id && !current_threads.contains(id)
+                    Some(id) != active_thread_id && !exclude_threads.contains(id)
                 }
                 ThreadContextEntry::Context { .. } => true,
             })
@@ -710,7 +742,7 @@ fn add_selections_as_context(
     })
 }
 
-fn selection_ranges(
+pub(crate) fn selection_ranges(
     workspace: &Entity<Workspace>,
     cx: &mut App,
 ) -> Vec<(Entity<Buffer>, Range<text::Anchor>)> {