## Why
Truncating diagnostic attachments can corrupt compressed archives, while skipping unreadable files can hide incomplete diagnostic delivery.
## What changed
- Remove attachment truncation and the 40,000,000-byte wire cap. Enforce the 200 MiB decoded envelope limit, including framing, and report oversized or unreadable attachments as upload failures.
- Use gzip only when it reduces envelope size, and set `Content-Encoding` according to the request bytes for both interactive and report uploads.
- Document that successful uploads mean HTTP acceptance, not durable attachment storage, and that callers must retain source files.
## Testing
Add coverage for incomplete uploads caused by missing or oversized files. Update large-file coverage to verify byte-for-byte delivery of JSONL files and a gzip archive exceeding the former wire cap, including successful archive decompression.
GitOrigin-RevId: a5316e9f407f16ee5a3dfb3f15122b1db51d6a94
## What changed
- Send the core report event before its attachments, then upload each attachment in a separate gzip-compressed envelope linked to that event.
- Bound encoded and decoded payload sizes, truncate oversized attachment copies with format-aware handling for JSONL, and preserve attachment priority when applying size limits.
- Retry transient attachment failures within a shared upload-time budget while honoring Sentry rate-limit and retry headers without replaying the core event.
- Add APIs to prepare and send persisted report events and attachments using a stable report ID, explicit delivery outcomes, and caller-controlled retries.
## Testing
- Cover attachment retries, truncation, rate limits, rejected responses, transport failures, redirect handling, content types, diagnostic consent, and report tags.
GitOrigin-RevId: 5eacd384843795d05d1c024b76e1c6d0c1c4b8d7
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