fix(flights): compose the map at the width the ticker asked for

[ChuckBuilds]

Follow-up to the observation that the flight map "is always a different size". It is — and which size you get depends on a code path the plugin cannot see.

What happens

Vegas asks a plugin for a narrower render so a full-panel layout doesn't read as sparse in the ticker. It normally delivers that by narrowing the shared canvas for the call, which a plugin sizing itself from matrix.width picks up for free.

But it cannot narrow the canvas in offscreen mode — _render_at swaps the shared canvas, which is unsafe there — so it only sets the hint. Core's own comment says as much:

_vegas_render_width is set regardless: a plugin reading get_vegas_render_width() still gets its narrow size, and one that only reads matrix.width renders full width and is trimmed instead.

This plugin relied on the canvas being narrowed; its docstring said the projection scales "without any extra plumbing". Measured over two hours on the rig, that held 3 times out of 12:

Native: requesting 256px instead of 512px
Native: SUCCESS - 1 images, 512px total width      <- cropped afterwards
Native: SUCCESS - 1 images, 256px total width

So the map was composed at twice the needed width and most of it thrown away, on 9 of 12 requests.

The fix

The width property reads the hint. It covers both paths and falls back to the panel width outside a Vegas request, so the rotation is untouched.

The composite cache is already keyed by size, and its comment already says "Rotation and Vegas render the same map at different widths" — so this adds a cache entry rather than invalidating one. That was worth checking before changing anything, given a size-keyed cache is exactly where I found a thrash in the radar last time.

Wider finding

No plugin in the repo read get_vegas_render_width() before this, despite core providing and documenting it. Nine others currently render full-width frames the adapter then trims:

plugin	rendered → kept	discarded
countdown	5632 → 957	83%
clock-simple	4608 → 927	79%
of-the-day	6144 → 1365	77%
incoming-packages	5120 → 1160	77%
stock-news	4608 → 1998	56%

They're candidates for the same treatment, but each needs its own layout thought — a tighter arrangement, not just a smaller canvas. This fixes the one with a measured problem.

Verification

test_vegas_render_width.py: the width follows the request, returns to the panel width afterwards, falls back on a nonsense hint (0, -1, "wide", None), and the cache still keys on size. Mutation-checked — reverting to matrix.width fails it. All 9 flights suites pass.

One trap the test caught, worth recording: the harness must set both display_manager and _display_manager_ref. This plugin keeps the private name; BasePlugin stores the same object under the public one, and get_vegas_render_width()'s fallback reads the public one. A stub with only the private name makes the fallback miss the matrix and return its hard-coded 128 — which looks exactly like the property being broken, and briefly convinced me the fix was wrong.

🤖 Generated with Claude Code

https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW

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[ChuckBuilds]

Superseded by #314, which combines the four ledmatrix-flights PRs into one version bump. Every change from this PR is verified present on that branch; the branch here is untouched if you want to compare.