TUI ext panel: typing in search input doesn't filter visible items

[JDonaghy]

Symptom

In an extension-provided sidebar panel, pressing `/` correctly activates the search input row (chrome flips into edit mode, cursor appears). Typed characters update `engine.ext_panel_input_text[panel_name]` and the text shows in the input row — but the item list doesn't filter.

Cause (suspected)

The engine doesn't filter items itself. It fires a `panel_input` plugin event (see `src/core/engine/ext_panel.rs` — the `/` handler at line ~242 flips `ext_panel_input_active = true` but no filter pass runs). Plugins are expected to subscribe to `panel_input` and re-emit a filtered item list via `set_items` — but no shipping plugin appears to do that, so user-facing behavior is "typing in the search box is a no-op visually".

Repro

1. Open any extension panel (e.g. `git_insights`).
2. Press `/`. Input row appears.
3. Type a substring of a visible item.
4. Item list does not narrow.

What good would look like

Either:

• Plugin-side fix per panel: each panel's plugin subscribes to `panel_input` and filters.
• Engine-side default filter: if the plugin doesn't intercept, the engine could provide a default case-insensitive substring filter over `item.text`. Trivial to add in `ext_panel_visible_indices()` since visibility already runs through there.

The engine-side default is probably better — it gives plugins a reasonable fallback while leaving the override hook in place.

Notes

Surfaced during smoke testing of #476 / PR #482. Migration didn't change the input or filter path; this behavior predates the TreeView migration.

[JDonaghy]

Agent Briefing — Server (Session 389, batch #483/#484/#485)

Batched assignment. Three TUI ext panel bugs, all in the same file group. Fix all three on one branch, one PR.

Bug 1: #483 — Search input doesn't filter items

• Root cause (suspected): Engine flips ext_panel_input_active = true on / but never runs a filter pass. Plugin panel_input event may not be firing, or the built-in filter path is missing.
• Files: src/core/engine/ext_panel.rs (filter logic), possibly src/tui_main/mod.rs (key dispatch)

Bug 2: #484 — Header click doesn't toggle expand

• Root cause (suspected): src/tui_main/mouse.rs:~2293 dispatches the click but the toggle doesn't stick — likely double-dispatch or the click selecting the row AND toggling (select overrides the toggle).
• Files: src/tui_main/mouse.rs (click dispatch)

Bug 3: #485 — Scroll wheel doesn't scroll panel

• Root cause (suspected): Wheel events for the ext panel area aren't routed to the panel's scroll handler. Scrollbar drag works because it goes through a different dispatch path.
• Files: src/tui_main/mouse.rs (wheel dispatch), possibly src/tui_main/panels.rs

Files you own

• src/tui_main/mouse.rs
• src/tui_main/panels.rs
• src/tui_main/mod.rs (key dispatch only)
• src/core/engine/ext_panel.rs

Do NOT touch

• src/gtk/ — Desktop A agent is there (Migrate GTK widget tree to quadraui AppShell + run_with_shell() #447)
• ~/src/quadraui/ — separate repo

Quality gate

cargo build --no-default-features
cargo test --no-default-features
cargo clippy -- -D warnings
cargo fmt --check

Branch

issue-483-485-tui-ext-panel-fixes

Push #475 first if you haven't already, then start this batch.