feat(parquet): prepare range and worker foundations

[ibgreen-openai]

Goals

• Harden shared byte-range infrastructure for Parquet, PMTiles, GeoTIFF, and other random-access sources.
• Make ParquetSource capabilities, cached state, cancellation, and package-local WASM delivery explicit.
• Keep the public HTTP random-access API understandable and directly documented.
• Continue feat(parquet): add reusable ParquetSource foundation #3529 and partially address [Parquet] Add reusable range-backed ParquetSource for scalable row-group streaming #3525 on top of the merged Parquet stack.

Changes

• Refactors HttpFile around exact validated byte ranges, pinned ETag/Last-Modified identity, strict or best-effort consistency, custom fetch options, cancellation, and immutable transport telemetry.
• Separates the 293-line HttpFile lifecycle/scheduler façade from the focused HTTP transport, response-validation, telemetry, and public-type modules.
• Recognizes valid empty HTTP objects from an opening 416 response with Content-Range: bytes */0, preserving validators and zero-length reads.
• Extends RangeRequestScheduler with explicit transport-context isolation, exact response validation, safe EOF clamping through authoritative source length, prompt per-caller cancellation, and network timing.
• Routes GeoTIFF and PMTiles range reads through the clarified scheduler contract while preserving per-source request isolation.
• Adds immutable ParquetSource capability reporting that reflects the current range-backed TypeScript source: statistics, custom transport, object validation, and network/decode telemetry are supported; source worker decoding remains deferred.
• Deep-freezes cached Parquet schema state, telemetry snapshots, and batch provenance, and preserves caller AbortSignal.reason.
• Publishes the bundler-safe @loaders.gl/parquet/wasm URL helper and raw WASM asset export, and updates parquet-wasm to 0.7.2.
• Adds focused coverage for identity changes, malformed/short responses, valid empty-object discovery, EOF clamping, coalescing, sibling cancellation, callback/source isolation, capability exports, immutable source state, abort reasons, and local WASM resolution.
• Moves browser-neutral HttpFile coverage into the shared test project and verifies it in Node and Chromium.
• Adds a dedicated HttpFile API reference covering opening, options, consistency modes, response requirements, methods, telemetry, cancellation, CORS, and scheduler sharing.
• Links the API page from the loader-utils overview/sidebar and corrects stale ReadableFile examples that used a nonexistent slice() method.
• Documents validated HTTP ranges, scheduler isolation, Parquet capabilities, and explicit package-local WASM workflows.

Current boundary

ParquetSource continues to use the selective TypeScript range backend merged in #3531, #3533, and #3535. It does not introduce the obsolete whole-file WASM source/session alternative from the pre-stack prototype. Worker-backed source decoding remains advertised as unavailable; the canonical WASM ParquetLoader worker path is already provided by #3538.

Validation

• yarn install
• yarn lint fix
• yarn build
• cd website && yarn build
• Focused Node suites — 8 files, 68 tests passed
• Focused Chromium suites — 6 files, 39 tests passed
• Shared HttpFile suite — 14 tests passed in Node and 14 in Chromium
• yarn test-node — 403 files passed, 3 skipped; 1,915 tests passed, 81 skipped
• yarn test-headless — 406 files passed, 3 skipped; 1,881 tests passed, 60 skipped
• GitHub Actions test workflow — 7 jobs passed
• git diff --check

Stack

• Base: master (fix(parquet): keep source runtime off package root #3530, feat(parquet): stream selective source batches #3531, feat(parquet): close TypeScript decoder gaps #3533, feat(parquet): add statistics, pruning, and telemetry #3535, and feat(parquet): add cancellable worker decode #3538 are merged)
• This PR: range/source foundations, capability hardening, and HTTP file API cleanup

Part of #3525.

[chatgpt-codex-connector]

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