Phase B.5c followup — lift find_replace into quadraui::{tui,gtk} (primitive migration)

[JDonaghy]

Goal

Lift the find/replace overlay rasterisers — TUI (src/tui_main/quadraui_tui.rs::draw_find_replace, ~280 lines) and GTK (src/gtk/draw.rs::draw_find_replace_popup, ~300 lines) — into quadraui::{tui,gtk}::*, mirroring B5c.5 / #266.

Split out from #266 because it is materially bigger than rich_text_popup / completions: it requires designing a new quadraui::primitives::find_replace (the other two were straight ports against existing primitives + theme fields).

Why bigger than the other lifts in #266

The find/replace rasterisers consume vimcode-private engine types:

• core::engine::FindReplaceClickTarget (enum, ~14 variants — Chevron, FindInput(usize), ToggleCase, PrevMatch, Close, ReplaceCurrent, …)
• core::engine::FrHitRegion (struct: col, row, width in cells)
• core::engine::FR_PANEL_WIDTH
• core::engine::compute_find_replace_hit_regions(panel_w, show_replace, match_info) -> (Vec<(FrHitRegion, FindReplaceClickTarget)>, u16)
• render::FindReplacePanel (the ScreenLayout field — query / replacement / focus / cursor / sel_anchor / match_info / hit_regions / etc.)
• crate::icons::FIND_REPLACE and crate::icons::FIND_REPLACE_ALL (Nerd Font glyph constants)

The two other lifts in #266 (rich_text_popup, completions) consumed only existing quadraui::* primitives + theme fields. find_replace requires inventing a new primitive in quadraui first, then migrating engine + render + both backends to use it.

Scope

1. New quadraui::primitives::find_replace with:
   • pub enum FindReplaceClickTarget (lifted verbatim from engine).
   • pub struct FrHitRegion (lifted verbatim).
   • pub const FR_PANEL_WIDTH: u16.
   • pub fn compute_hit_regions(panel_w, show_replace, match_info) -> (Vec<(FrHitRegion, FindReplaceClickTarget)>, u16).
   • pub struct FindReplacePanel { /* the data the rasteriser reads */ }.
2. Engine adoption:
   • core::engine::* re-exports the lifted enum/struct so existing call sites keep working unchanged, OR the engine imports them back from quadraui (preferred).
   • compute_find_replace_hit_regions either becomes a thin wrapper around the quadraui function, or is replaced at call sites.
3. Render adoption:
   • render::FindReplacePanel → either becomes an alias for quadraui::FindReplacePanel or the engine builds a quadraui::FindReplacePanel directly into ScreenLayout.
4. Icon constants: the two crate::icons::FIND_REPLACE* glyphs need a backend-agnostic representation. Options:
   • Pass them in via the FindReplacePanel data (e.g. replace_one_glyph: char, replace_all_glyph: char). Lets the app choose Nerd Font vs ASCII fallback.
   • Keep them in vimcode and add backend-specific glyph fields.
5. Lifted rasterisers:
   • quadraui::tui::draw_find_replace(buf, area, panel, theme, editor_left) — port of the TUI shim body.
   • quadraui::gtk::draw_find_replace(cr, layout, panel, theme, line_height, char_width, editor_left) — port of the GTK draw.rs body.
6. Both backend shims then collapse to thin delegators.

Why defer rather than do this in #266

#266 says "mostly mechanical" lifts. The other two (rich_text_popup + completions) genuinely were. find_replace ends up reshaping engine and render adoption, which is one stage of work in itself, and would have made #266's PR materially harder to review.

Pickup files

• src/core/engine/mod.rs lines 1060-1210 (FindReplaceClickTarget, FrHitRegion, FR_PANEL_WIDTH, compute_find_replace_hit_regions).
• src/render.rs line 3410+ (FindReplacePanel, the re-export at line 3406).
• src/tui_main/quadraui_tui.rs::draw_find_replace (the body the lift will copy).
• src/gtk/draw.rs::draw_find_replace_popup (same).
• src/core/engine/execute.rs::handle_find_replace_click and similar — engine-side dispatchers that consume the enum.
• src/icons.rs — FIND_REPLACE / FIND_REPLACE_ALL.

Surfaced during

#266 — only the rich_text_popup + completions lifts shipped under #266.

[JDonaghy]

Shipped on develop in 91e89e9.

New quadraui::primitives::find_replace module with the lifted enum + struct + const + compute_hit_regions function + FindReplacePanel data shape. replace_one_glyph: String and replace_all_glyph: String fields on the panel carry app-supplied glyph strings so the primitive doesn't depend on any host app's icon registry. compute_hit_regions takes replace_one_glyph_width: u16 + replace_all_glyph_width: u16 parameters.

quadraui::tui::draw_find_replace + quadraui::gtk::draw_find_replace rasterisers lifted from the vimcode shims; quadraui::Theme grew accent_bg for toggle highlight backgrounds.

Vimcode adoption: core::engine::* and render::* re-export the lifted types so existing call sites compile unchanged. render::FindReplacePanel is now a type alias for quadraui::FindReplacePanel.

Net diff -681/+64 lines (the two large bespoke rasteriser bodies are deleted). Closes the last 'trait-less primitive' gap on the find/replace overlay; quadraui now has 278 tests passing; vimcode + kubeui-gtk build clean.