Prepare Lodstone progressive streaming alpha

[kephale]

Summary

• add renderer-neutral progressive multiscale planning, streaming, cancellation, caching, and diagnostics
• compose bounded dense resident windows from coarse-to-fine while preserving directly loaded data
• share runtimes across layers and channels and stage CPU-heavy publication work off viewer threads
• add experimental napari and ndv adapters, including camera-driven dense focus windows
• refine perceptual canvas-coverage versus depth-reach sampling and sparse-aware coarse masking
• add explicit NDV contrast normalization, VisPy/PyGFX demo selection, and projected-block diagnostics
• add alpha compatibility documentation, cross-platform CI, package version metadata, and a trusted PyPI publishing workflow

The renderer-neutral core is the compatibility boundary for the 0.1 series. Viewer adapters remain experimental while their host APIs are upstreamed and released.

Validation

• 161 passed on Python 3.13 locally
• Ruff check and format pass
• Pyright: 0 errors
• wheel and sdist build and pass twine check
• clean-environment wheel install passes with ome-zarr and datasets extras
• GitHub workflow security audit reports no findings
• napari progressive integration: 91 passed
• ChimeraX native integration: 74 passed with Zarr 3.1.6 and 74 passed with Zarr 3.3.0; bundle build succeeds
• ndv integration: 189 passed, 14 skipped

GitHub Actions jobs for this repository are currently prevented from starting by the account billing/spending-limit setting. Each check has zero executed steps and the GitHub annotation reports that billing must be corrected; the same commands pass locally.

Downstream integrations

• napari: Integrate LodStone progressive multiscale loading napari#34
• ndv: feat: expose canvas integration and camera APIs pyapp-kit/ndv#285
• ChimeraX OME-Zarr: feat: add Lodstone progressive streaming uermel/chimerax-ome-zarr#22

[kephale]

Follow-up 1f11e01 makes planning non-mutating (Stream.plan) and makes replanning during an in-flight generation conservatively redeliver desired tiles. This prevents a target that replaces pending residency from inheriting an invalid availability assumption.

Validated locally: 126 tests pass; Ruff passes.

[kephale]

LOD policy follow-up is in a10a186: adapters can now cap intermediate progressive levels without changing the default ladder, and can pass a previous target plus hysteresis when planning. Napari behavior remains unchanged by default.

Validation: 128 tests pass; Ruff passes.

[kephale]

Post-debounce follow-up (8416885):

• adds off-host stage_prepare and stage_phase lifecycle hooks
• records prepare/update/phase CPU staging time in StreamDiagnostics
• makes ResidentArrays and ResidentLease key access explicitly synchronized
• exposes allocation/fill, overlap-copy, and composition timing callbacks

Validation: 142 tests pass; Ruff, format, and Pyright are clean; CI is green on Python 3.11–3.14.