Decompose render: left sidebar as View<SidebarPanel> with SidebarSnapshot

[MasonRhodesDev]

Context

While auditing the render architecture in #203, the left sidebar was identified as the highest-payoff decomposition target.

Currently left_sidebar.rs is a collection of &self render helpers called inline from AnotherOneApp::render. Any state change anywhere in the app triggers a full re-render of the sidebar even when its specific state (project list, task list, expand state, context menus) didn't change.

What to do

Mirror the existing RightSidebarPanel pattern exactly:

1. Define a SidebarSnapshot struct capturing everything the sidebar needs: projects, tasks, expanded repo IDs, UI state (pinned tasks, last active section), and the per-task menu/rename/delete-confirm state that currently lives on AnotherOneApp.
2. Create struct SidebarPanel implementing Render, storing the snapshot plus local interaction state (sidebar_task_menu, sidebar_task_rename, sidebar_task_delete_confirm, sidebar_task_last_click).
3. Store sidebar_panel: Entity<SidebarPanel> on AnotherOneApp.
4. In the drain tick, compute a fresh SidebarSnapshot only when project/task state actually changed (gate behind a dirty flag like sidebar_changed), push it to SidebarPanel and call cx.notify() on it. Terminal-output ticks must not notify the sidebar.
5. Remove the sidebar-only fields from AnotherOneApp (5–6 fields).

Why this is the right next step

• RightSidebarPanel already proves the pattern works in this codebase.
• The sidebar's state drivers (project/task mutations, daemon ProjectList pushes) are low-frequency (<1/sec) and already separated from terminal-output ticks by the drain loop.
• Sidebar context-menu state (sidebar_task_menu, etc.) has zero cross-cutting dependencies — it can move directly into the new view.
• project_store is the only broad dependency; a SidebarSnapshot severs it cleanly.

[MasonRhodesDev]

Implementation plan

Fields AnotherOneApp currently exposes to left sidebar render code

Snapshot-eligible (read-only, sourced from daemon/store state):

Field	Type	Used for
project_store.projects	Vec<Project>	Group rows, delete confirm
project_store.tasks	HashMap<String, Vec<Task>>	Task rows, linked issues
project_store.ui.theme_mode	ThemeMode	Every row
project_store.ui.pinned_task_ids	HashSet<String>	Pin indicator, row sort
project_store.ui.show_sidebar_git_metadata	bool	Branch metadata strip
expanded_projects	HashSet<String>	Chevron state
project_expand_animations	HashMap<String, SidebarProjectExpandAnimation>	Animated expand height
project_github_links	HashMap<String, String>	GitHub icon on project row
project_pull_requests	HashMap<String, PullRequestStatus>	PR dot on branch row
changed_files	HashMap<String, Arc<[ChangedFile]>>	Unstaged warning in delete confirm
workspace_pane.active_section	Option<SectionId>	Highlight active branch row
workspace_pane.active_project_page	Option<String>	Highlight active project row

Sidebar-local state (moves to SidebarPanel):

Field	Type
sidebar_task_menu	Option<SidebarTaskMenuState>
sidebar_task_delete_confirm	Option<SidebarTaskDeleteConfirmState>
sidebar_task_rename	Option<SidebarTaskRenameState>
sidebar_task_last_click	Option<(String, String, Instant)>
project_menu_project	Option<String>
project_remove_confirm	Option<ProjectRemoveConfirmState>

SidebarSnapshot struct

#[derive(Clone, Default)]
pub(crate) struct SidebarSnapshot {
    pub theme_mode: ThemeMode,
    pub projects: Arc<[Project]>,
    pub tasks: Arc<HashMap<String, Vec<Task>>>,
    pub expanded_projects: HashSet<String>,
    pub project_expand_animations: HashMap<String, SidebarProjectExpandAnimation>,
    pub project_github_links: HashMap<String, String>,
    pub project_pull_requests: HashMap<String, PullRequestStatus>,
    pub changed_files: HashMap<String, Arc<[ChangedFile]>>,
    pub pinned_task_ids: HashSet<String>,
    pub show_sidebar_git_metadata: bool,
    pub active_section: Option<SectionId>,
    pub active_project_page: Option<String>,
}

SidebarPanel struct

pub(crate) struct SidebarPanel {
    pub app: WeakEntity<AnotherOneApp>,
    pub snapshot: SidebarSnapshot,
    // Local UI state — survives snapshot updates
    pub sidebar_task_menu: Option<SidebarTaskMenuState>,
    pub sidebar_task_delete_confirm: Option<SidebarTaskDeleteConfirmState>,
    pub sidebar_task_rename: Option<SidebarTaskRenameState>,
    pub sidebar_task_last_click: Option<(String, String, Instant)>,
    pub project_menu_project: Option<String>,
    pub project_remove_confirm: Option<ProjectRemoveConfirmState>,
}
impl Render for SidebarPanel { … }

Mirrors RightSidebarPanel exactly. WeakEntity<AnotherOneApp> for all write-back calls; cx.defer for snapshot pushes to avoid double-lease.

Step-by-step plan (each step independently mergeable)

Step 1 — Add SidebarSnapshot struct (no behaviour change)
Add the struct + Default impl to left_sidebar.rs. Dead code until step 2.

Step 2 — Add SidebarPanel entity with stub Render
Add struct SidebarPanel + impl Render returning empty div(). Add left_sidebar_panel: Entity<SidebarPanel> to AnotherOneApp. Entity is created in new() but not rendered anywhere. Existing sidebar_content untouched.

Step 3 — Add build_sidebar_snapshot + sync_sidebar_snapshot
Modelled on build_right_sidebar_snapshot / sync_right_sidebar_snapshot:

pub(crate) fn sync_sidebar_snapshot(&mut self, cx: &mut Context<Self>) {
    let snapshot = self.build_sidebar_snapshot(cx);
    let panel = self.left_sidebar_panel.clone();
    cx.defer(move |cx| {
        panel.update(cx, |panel, cx| { panel.snapshot = snapshot; cx.notify(); });
    });
}

Wire from: cx.observe(&workspace_pane, ...), after absorb_projection, drain-loop should_notify branch.

Step 4 — Migrate render helpers to impl SidebarPanel (main effort)
Move sidebar_groups, branch_row, project_row, sidebar_task_menu_panel, project_menu_overlay, and all helpers so they read self.snapshot.* instead of self.project_store.*. Mouse handlers that previously called AnotherOneApp methods directly now go through self.app.update(cx, |app, cx| { … }). Implement Render fully. Replace self.sidebar_content(window, cx) call sites with AnyView::from(self.left_sidebar_panel.clone()).cached(...).

Step 5 — Remove 6 fields from AnotherOneApp
Remove sidebar-local fields. Update clear_removed_project_references, handle_global_key_down, handle_sidebar_task_rename_key_down, should_show_controls_hud, and modal overlay call sites to go through left_sidebar_panel.update(cx, …) / left_sidebar_panel.read(cx).

Step 6 — Wire remaining sync_sidebar_snapshot call sites
Ensure sync_sidebar_snapshot is called from: toggle_project_expansion, drain_project_pull_request_lookup, drain_remote_worker_replies (after absorb_projection). Missing a call site causes a stale snapshot — caught by smoke testing.

Action dispatch analysis

Sidebar click handlers currently call this.<method>() directly on AnotherOneApp via cx.listener. After step 4 they run in Context<SidebarPanel>. Mutations to local state (sidebar_task_menu, sidebar_task_rename, etc.) call self.<field> directly. Mutations that need AnotherOneApp (activate section, daemon verbs, show toast) go through:

self.app.update(cx, |app, cx| {
    app.workspace_pane.update(cx, |workspace, cx| {
        workspace.activate_section(…, cx);
    });
})

This is the same pattern RightSidebarPanel uses throughout.

Risks

Stale snapshot on animation ticks. project_expand_animations changes every frame during an expand. Options: (a) call sync_sidebar_snapshot from the animation ticker (snapshot-per-frame cost), or (b) move animation state into SidebarPanel local state entirely — it is UI-only; the persisted target is daemon state. Recommended: move to local state. The snapshot only captures the animation target state; the panel owns the per-frame interpolation.

Double-borrow in cx.defer. Never call left_sidebar_panel.update from inside AnotherOneApp::render — only from the timer closure or event handlers. Same rule as sync_right_sidebar_snapshot.

handle_global_key_down key routing. ESC branches test self.sidebar_task_rename.is_some() etc. After migration these become self.left_sidebar_panel.read(cx).<field>.is_some(). Key events still arrive at AnotherOneApp; panel mutations go through left_sidebar_panel.update.

clear_removed_project_references touches 6 migrated fields. Delegate to a SidebarPanel::clear_project_references(&mut self, project_id: &str) method called via left_sidebar_panel.update.

Acceptance criteria

• SidebarPanel is an Entity<SidebarPanel> rendered via .cached() in both the wide layout and the narrow MobileView::Home branch
• AnotherOneApp no longer holds sidebar_task_menu, sidebar_task_delete_confirm, sidebar_task_rename, sidebar_task_last_click, project_menu_project, project_remove_confirm
• sidebar_content method removed from AnotherOneApp; all logic in SidebarPanel
• Pure terminal-output ticks do not re-render the sidebar panel
• Project list, task rows, expand animations, PR dots, GitHub icons, double-click rename, right-click context menu, worktree delete confirm, and project remove confirm all work identically
• cargo test -p app passes

Estimated scope

~+175 lines net. left_sidebar.rs stays roughly the same size (~3800 lines ± 200); app.rs shrinks by ~60 lines.