Audit src/tui_main/ for per-backend code that can be lifted or removed

[JDonaghy]

Goal

Identify all code in src/tui_main/ that duplicates logic available in src/render.rs, src/core/, or quadraui primitives — and file individual issues for each dedup opportunity found.

What to look for

1. Rendering logic that re-derives what render.rs or quadraui already computes (layout math, color mapping, text truncation)
2. Mouse/click handling that re-implements hit-testing available via cached quadraui layouts (StatusBarLayout, TreeViewLayout, PaletteLayout, etc.)
3. Event dispatch patterns that could be consolidated into engine methods (similar to how GTK is converging via Migrate GTK event dispatch to ShellApp::handle(UiEvent) #448)
4. Layout calculations that duplicate render::compute_editor_layout() or similar shared functions
5. Scroll handling outside of dispatch_scroll — any manual scroll math that should route through quadraui's shared scroll dispatch

What NOT to do

• Don't fix anything — just audit and file issues
• Don't touch src/gtk/ or src/core/engine/keys.rs
• Don't count thin wiring code (1-3 lines calling a shared function) — that's expected per-backend glue

Output

A set of new GitHub issues, each describing:

• Which function/block in src/tui_main/ is duplicated
• What shared code already exists (or what quadraui primitive would replace it)
• Estimated lines removed
• Any quadraui gaps that would need to be filed first

Context

The GTK side has a clear convergence chain (#447 → #448 → #449). The TUI side doesn't have one yet. This audit creates the TUI convergence backlog.

[JDonaghy]

Audit complete — 7 vimcode issues + 1 quadraui issue filed

Audited all four large TUI files (mod.rs 3.4k, mouse.rs 3.1k, panels.rs 2.4k, render_impl.rs 2.0k). Filed issues are grouped by tier so the backlog can be picked up in order of unblockedness:

Tier 1 — Ready now (no quadraui gap)

#	Lines	Title
#475	~80	TUI: Unify sidebar panel key translation into a shared helper
#476	~326	TUI: Add ext_panel_to_tree_view() builder and migrate Extension Panel to TreeView

Tier 2 — Small gap (minor render.rs/quadraui addition)

#	Lines	Title
#477	~40	TUI: Use compute_tab_bar_hit_regions() / cached TabBar layout for drag slot bounds
#478	~200	TUI: Migrate sidebar-item hover popup to a shared tooltip builder

Tier 3 — Blocked on quadraui (new primitives needed)

#	Lines	Title	Blocked on
#479	~312	TUI: Migrate Settings inline-edit path to FormController (cursor support)	quadraui Form text-cursor
#480	~360	TUI: Migrate Source Control panel (commit row, branch picker, help dialog) to shared primitives	TextInput, ButtonBar, Palette dual-mode, Dialog rich content
#481	~120	TUI: Migrate window-separator scrollbar drawing + tab drop overlay to quadraui primitives	Backend::draw_scrollbar(), drag-drop primitive

Filed on quadraui

Repo	#	Title
JDonaghy/quadraui	#218	Add ChatPanelView primitive (message list + input box) for AI/chat sidebars

Findings dropped after spot-check

• Editor hover popup — already routes through editor_hover_to_quadraui_rich_text() + draw_rich_text_popup(). Only the sidebar-item hover popup is hand-rolled (TUI: Migrate sidebar-item hover popup to a shared tooltip builder #478).
• Scrollbar v/h track-click duplication in mouse.rs — internal v/h symmetry, not a shared-API gap. GTK doesn't call scrollbar_click_to_scroll_top() either; the current TUI page-jump UX is intentional and the shared function does proportional-jump (different behavior). Not a convergence finding.

Total addressable

~1,440 lines of TUI-specific code identified for removal once all blockers clear. Mirrors the GTK convergence chain shape (#447 → #448 → #449).

[JDonaghy]

Audit complete. 7 vimcode issues (#475-#481) + 1 quadraui issue (#218) filed. See tiered backlog in audit comment.