fix(server): disable unsupported summaries for Codex Spark

[astartsky]

Linked issue

Closes #2646

Type of change

• Bug fix
• New feature (with prior issue + design alignment)
• Refactor / code improvement
• Docs

What does this PR do

Codex 0.144.4 applies the global reasoning-summary setting to Spark, but gpt-5.3-codex-spark rejects reasoning.summary with a 400 unsupported_parameter response.

This change scopes the compatibility override to the built-in Codex provider and Spark model:

• thread/start and thread/resume receive model_reasoning_summary = "none".
• Every Spark turn/start uses the protocol-supported summary: "none" override.
• Switching away from Spark restores the configured Codex summary value for subsequent turns.
• Custom Codex-derived providers and users with no configured summary are left unchanged.

The per-turn override matters for already-loaded threads: turn/start.config is not part of the Codex app-server protocol, while turn/start.summary is.

How did you verify it

Automated coverage in codex-app-server-agent.test.ts verifies:

• a new Spark thread;
• a resumed Spark thread;
• Sol → Spark → Terra in one existing thread (concise → none → concise);
• a custom Codex-derived provider using the Spark model ID;
• a non-Spark model with no configured summary.

Commands run on the final branch after rebasing onto origin/main:

• npm run build:server
• npx vitest run packages/server/src/server/agent/providers/codex-app-server-agent.test.ts --bail=1 — 119/119 passed
• npm run typecheck
• npm run lint — 0 warnings, 0 errors
• npm run format:check
• git diff --check origin/main...HEAD

Real provider verification:

1. Ran the patched daemon with Codex CLI 0.144.4 and model_reasoning_summary = "concise".
2. Created a real codex/gpt-5.3-codex-spark agent through Paseo with low thinking and auto-review mode.
3. Sent Reply with exactly SPARK_OK. Do not use tools.
4. The agent completed with SPARK_OK; the daemon log contained no unsupported_parameter or reasoning.summary failure for that agent.

Checklist

• One focused change. Unrelated cleanups split out.
• npm run typecheck passes
• npm run lint passes
• npm run format ran
• UI evidence is not applicable (server-only fix)
• Tests added or updated where it made sense

[greptile-apps]

Greptile Summary

This PR prevents unsupported reasoning summaries from reaching the built-in Codex Spark model.

• Applies none to Spark thread start, resume, and per-turn requests.
• Restores the configured summary when switching to another built-in Codex model.
• Excludes custom Codex-derived providers from the compatibility override.
• Adds regression coverage for new, resumed, switched-model, custom-provider, and unconfigured-summary sessions.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the previous custom-provider issue is fixed by gating both the thread-level compatibility override and turn-level summary handling on the absence of a custom provider.

Important Files Changed

Filename	Overview
packages/server/src/server/agent/providers/codex-app-server-agent.ts	Adds a built-in-provider-only Spark compatibility override and resolves configured reasoning summaries for each turn.
packages/server/src/server/agent/providers/codex-app-server-agent.test.ts	Covers Spark thread lifecycle behavior, model switching, absent defaults, and preservation of custom-provider settings.

_{Reviews (2): Last reviewed commit: "fix(server): preserve custom Codex summa..." | Re-trigger Greptile}