[ael-dev3]

Raises the video limit from 50 to 250 MB with authenticated 8 MB multipart uploads. Retry continues from the last acknowledged chunk; Remove cancels the reservation, and the composer shows preparation, upload progress and completion before allowing the cast to send.

Compatible MP4/MOV files are repackaged for HLS from bounded metadata and file slices, preserving their samples without copying the whole video into WebAssembly. The Worker streams parts into R2 and retains account ownership, atomic quota reservations, bounded upload work, cancellation fencing and idempotent completion. Image, per-account daily and total storage limits remain unchanged. No new provider, secret, paid transcoding service or dependency is added.

Two existing browser-fixture setup races are also made deterministic: a seen feed is restored before autocomplete interaction, and delayed profile facts remain held until initial geometry is measured. Their original assertions and timing limits remain.

Validation:

• Required local fmt/Clippy/native+wasm/license checks: 612 native tests passed; 28 tooling checks passed.
• Composer attachments: 20 passed without retries, including lost responses, opaque receipts and reclaimed sessions.
• Real local Worker/R2/D1: 12 passed without retries, including all 32 parts of a 250 MB upload, byte ranges, accounting, ownership, cancellation and completion replay.
• Controlled original fixture preconditions fail; corrected copies pass under the same delays. The official eight fixture cases pass without retries.
• Full functional: 790 passed / 21 declared skips; isolated strict smoothness: 70 passed / two existing fixmes; static: 17 passed / 12 declared skips. Zero failures or retries. All 921 existing test IDs remain, plus 13 new regressions.