perf(server): skip full-message reads while streaming

[Zain-Repo]

What changed\n- Add an atomic SQLite append operation for streaming projected messages.\n- Preserve creation timestamps and omitted attachments while appending deltas.\n- Keep completion events on the existing replace-or-preserve path.\n\nReviewed against upstream PR #9032: https://github.com/pingdotgg/t3code/pull/9032\n\nValidation: targeted ProjectionThreadMessages and ProjectionPipeline tests pass (25 tests).

[Zain-Repo]

@codex review Please review the latest commit for correctness, SQLite upsert semantics, attachment preservation, and missing validation.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-01T21:49:43.023608Z	0081473	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🚀

Reviewed commit: 0081473f96

ℹ️ About Codex in GitHub

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