Add pan/zoom interaction switches for static-viewport charts

[FarhanAliRaza]

Problem

XY charts are interactive by default, but interaction_config() only configured hover, click, selection, brush, crosshair, view-change events, and linked views — there was no supported way to make a chart's viewport static. Dashboard charts intended as fixed summaries could still be drag-panned or wheel-zoomed, leaving bars or axes partially out of view. Hiding the modebar does not disable the gestures, and disabling pointer events on a framework wrapper is brittle because the chart's canvas owns the interaction handlers.

API

chart = xy.bar_chart(
    xy.bar(["A", "B", "C"], [10, 20, 30]),
    xy.interaction_config(pan=False, zoom=False),
)
# or equivalently as chart-level kwargs: xy.bar_chart(..., pan=False, zoom=False)

• pan=False — plain-drag pan gestures are ignored; the modebar Pan button is hidden. Shift-drag / box select stay governed by select/brush.
• zoom=False — wheel zoom, box-zoom, and double-click reset are ignored; the modebar zoom controls (Zoom In/Out, Box Zoom, Reset View, percent label) are hidden. Double-click still clears selection.
• Defaults remain enabled: the flags serialize only when explicitly set, and the client treats an absent key as enabled, so existing specs are byte-identical.
• Hover, click, and selection remain independently configurable and functional on a static chart.

Behavior details

• With zoom=False the wheel handler returns before preventDefault(), so the page scrolls naturally over a static chart embedded in a dashboard.
• With pan disabled, the drag-tracking object is never created; a stationary press still fires click/pick events and hover is unaffected.
• A chart with both flags disabled ignores inbound linked-view (link_group) updates; with only one disabled, linked updates still apply.
• Non-bool values raise ValueError via the existing centralized interaction validation.
• No Rust/ABI changes — interaction config never touches the core. python/xy/static/ regenerated via node js/build.mjs.

Testing

• New tests: explicit pan/zoom serialization (True and False), chart-level kwargs, and ValueError on non-bool values (tests/test_components.py).
• Existing exact-dict interaction spec tests pass unmodified aside from the deliberately extended declarative-contract test — confirming defaults serialize nothing.
• Full suite: 2021 passed. ruff check, ruff format --check clean; ty check has one pre-existing diagnostic unrelated to this change (present on a clean tree).

Closes #80

[codspeed-hq]

Merging this PR will not alter performance

✅ 94 untouched benchmarks
⏩ 1 skipped benchmark¹

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_{Comparing feat/interaction-static-pan-zoom (58a60c6) with main (3c5054f)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

[Alek99]

Review findings:

• [P2] js/src/50_chartview.js:914: charts with pan and zoom disabled still set touch-action:none, so a touchscreen swipe over a static chart cannot scroll the containing dashboard. Make touch-action depend on enabled gestures/drag mode.
• [P3] js/src/53_interaction.js:1205: pan-disabled charts still initialize dragMode="pan" and show a grab cursor even though plain dragging does nothing. Initialize/sanitize the mode from the enabled interactions.