feat(request-trace-uploader): parse v1.4.0 records and add initial object-store upload

Why

The uploader scaffold only discovers closed Dynamo request-trace segments. The next increment should prove the narrow happy path, and pin the record format it depends on, before adding durable recovery and configurable policy complexity.

Scope

• Parse the Dynamo v1.4.0 RequestTraceRecord format. All five event types (request_end, request_payload, tool_start, tool_end, tool_error) must parse, including records where the optional request, payload, and tool members are absent.
• Resolve the request identifier from request.request_id on request_end and payload.request_id on request_payload. Parse both the bare record form and the timestamp-wrapped form.
• Detect the Dynamo v1.3.x AuditRecord shape and fail with an explicit version error rather than mis-parsing or silently discarding records.
• Export records carrying an unrecognized event type or unrecognized fields with content preserved verbatim, counted rather than dropped.
• Isolate parse failures per record. A record that fails to parse must not fail the segment containing it: skip it, preserve its raw bytes for inspection, count it, and continue. Quarantine the segment only when a configured proportion of its records fail.
• Classify records by event_type only. Dynamo v1.4.0 writes a single file family; there is no separate audit directory or prefix.
• Define the backend interface with separate submit and confirm steps, and a capability declaration covering resubmit safety, terminal-outcome timing, out-of-order tolerance, accepted formats, and maximum object size.
• Implement the generic S3-compatible object-store backend against that interface.
• Read the next closed segment, transform it into the format the selected backend declares it accepts, submit it, and delete the source only after a successful upload response.
• On a failed read, parse, transform, upload, or delete, retain the source file and return the error through structured logs and telemetry.
• Process one closed segment at a time. Do not add background queues, retries, persistent state, status polling, quarantine, or automatic deployment injection in this increment.

Tests

• Closed-versus-active segment selection.
• Every event type, including absent optional members, and both record forms.
• Fixtures captured from a running Dynamo instance at the pinned version, with the producing version recorded alongside them.
• v1.3.x AuditRecord input produces a version error.
• Unknown event type and unknown field preservation.
• Successful read, transform, upload, and source deletion.
• Read, transform, upload, and delete failure paths that retain the source and produce bounded telemetry.
• Concatenated gzip input and destination-envelope tests.

Follow-on work:

• Durable lifecycle state and failure quarantine.
• Configurable upload policies.
• Kratos Bulk Upload backend.
• Record suppression and sampling.
• Full observability and documentation.

Parent: #1004

Start by locating the request-trace-uploader scaffold, closed-segment reader, and existing tests for segment selection and record parsing. Done means v1.4.0 records and failure paths are covered, the S3-compatible backend submits and confirms through the declared interface, and a source segment is deleted only after successful upload.