ui(shell): un-collide the top-right status cluster, tip the transport bar, keep the audio graph out of the clips browser

[jeffcrouse]

Three shell-chrome defects reported against the running app, plus the geometry test that would have caught two of them.

1. The top-right status cluster collided

The ADR-0019 health rollup dot (layout.h, win_w - 26) and the always-on perf read-out (frame.cpp, right-aligned at win_w - 8) were two independent right-edge anchors, neither aware of the other. The dot's full 12px width landed inside the chip — and because the chip draws last at 0.60 alpha, it read as a green smudge under the fps text rather than a status light.

Both now derive from one gutter constant: health_dot_rect pins to kTopRightPad, and the new perf_hud_rect anchors off it and grows leftward as the string gets longer. Both are vertically centred on the 40px bar, so the cluster reads as one row.

2. No tooltips on the transport bar

There was no tooltip mechanism in the app at all — every control re-derives hov each frame and throws it away, and nothing tracked dwell.

New ui/tooltip.h holds the one piece of state an immediate-mode UI can't recompute: how long the cursor has been on the same item. It reuses hover_status() (the clip/sampler editors' existing "what will happen" pill) as its body rather than introducing a second chrome vocabulary.

session_view::tick_top_bar_tooltip walks the same layout.h rects the draw and the hit-tests use, so a moved control can't leave its tooltip behind. It runs in the frame loop's overlay pass — after the perf HUD (whose text-driven rect it tips) and last of all, so the pill sits above every other overlay. Suppressed over a modal and mid-drag.

Tips carry the cheat-sheet's shortcut letters (Space / R / H). The health dot's also reports its current rollup, so hovering answers "is anything wrong?" without opening the panel.

TipState.anchor is a placement rect, not the hit rect — the transport row passes a common band so the pill doesn't bob as the cursor crosses controls of differing heights.

3. The audio graph painted over the CLIPS browser

audio_graph_pane hard-coded x = kPaneMargin. The session grid escapes this via draw_ui's set_transform(SW,0,1), but that transform and its clip are torn down before the audio graph draws — it runs in raw screen space (and agr.draw sets its own camera, which would clobber the shift anyway), so the offset has to live in the rect.

The pane now takes sidebar_w, exactly as sidebar_panel / pool_item_rect already do. Because prime / ag_pane_hit / on_down share the helper, this also fixes an unreported input bug: scrolling over the CLIPS panel was zooming the audio graph (clicks were saved only by dispatch order).

Not a code defect

The reported "+ Note button still in the visuals graph" was a stale binary — the button was removed in #348 and the running build predated it. No change here.

Tests

New test_shell_layout (pure layout.h, headless) pins both geometry invariants, neither of which a compiler can see:

• the cluster never intersects, across a spread of window widths x text widths; the chip stays strictly left of the dot; both stay on-screen and share a vertical centre
• the chip is right-anchored (longer text extends left, never toward the dot)
• the audio pane is byte-identical to the old geometry when the browser is closed
• with the browser open it clears the CLIPS panel, still stops short of the splitter, and keeps its vertical span
• a window narrow enough that the splitter sits left of the sidebar still yields a non-degenerate rect (a negative width would blow up the scissor)

227 checks. Full suite: 100/100.

Verified live

On the blob project, driven with synthetic input:

• cluster separated and centred
• all seven tips render at a consistent baseline; the two right-edge tips clamp inside the window
• browser open → no overlap, CLIPS fully visible
• scroll over CLIPS is inert (graph layout byte-identical; only the live waveform animates)
• audio-node clicks still hit correctly at the new offset (dock switches to the node's params)

🤖 Generated with Claude Code

[github-actions]

Production gate (core): ✅ PASS

• 83/83 tests passed (0 failed) in 16.453s