feat(tracing): add portable journal file exporter

[sklinglernv]

What does this PR do?

• Adds an opt-in exporters.journal_file() exporter that writes append-only session.nooa.jsonl artifacts containing message-stripped OTLP spans and content-addressed journal block/call records.
• Extends nooa import-traces and nooa import-harbor to stream the new records into the viewer and remap journal session IDs consistently with renamed files and Harbor trials.
• Preserves all existing exporter defaults and supports HTTP and file journal callbacks simultaneously in either construction order.
• Adds end-to-end reconstruction, Harbor remapping, deduplication, coexistence, and factory coverage.

This persists the existing journal protocol; true snapshot-delta encoding of the remaining full hash skeleton is intentionally left for a follow-up.

Related issues

None.

Validation

• Commit hooks: Ruff, Ruff format, Pyright, SPDX, and repository checks passed.
• Broad tracing/import suite: 190 passed.
• Focused final suite: 14 passed.

Checklist

• Code follows the project style (Ruff and format checks pass)
• Tests added/updated and passing
• Docs updated for the new public exporter API
• New source files carry an SPDX license header

[sklinglernv]

End-to-end validation completed against a real NOOA viewer on localhost:5001.

• Ran a real synchronous LiteLLM request against a temporary OpenAI-compatible HTTP endpoint with exporters.journal_file enabled.
• Produced a 2,869-byte, five-record e2e-journal-pr116-8c41d6.nooa.jsonl artifact: manifest, two content-addressed blocks, one call record, and one stripped OTLP span.
• Verified both SHA-256 block hashes, single-copy input/output bodies, stripped LLM payload attributes, and call-to-span correlation.
• Imported the artifact with nooa import-traces: 1 imported, 0 skipped.
• Flushed and queried the viewer APIs; one span and one linked call were present, and /api/trace/export reconstructed E2E_INPUT_MARKER and E2E_OUTPUT_MARKER as standard OpenInference message attributes with total token count 10.

All end-to-end assertions passed.

[furgalep]

LGTM

[furgalep]

Approve