fix(codex): preserve context config in remote sessions

[NightWatcher314]

Summary

• read the effective Codex configuration from codex app-server using config/read
• forward model_context_window and model_auto_compact_token_limit through the shared thread config
• apply the same values to fresh, resumed, forked, /compact, and /goal thread paths
• fail open for older Codex runtimes that do not support config/read

Closes #1631.

Why

HAPI remote sessions use codex app-server and per-thread configuration. Without explicitly preserving these two effective config values, a selected model can fall back to its catalog context window even when direct Codex sessions honor larger values from ~/.codex/config.toml.

Validation

• bun run typecheck
• bun run test
• targeted Codex tests: 117 passed
• live read-only protocol probe against Codex CLI 0.147.0 confirmed config/read returns:
  • model_context_window = 400000
  • model_auto_compact_token_limit = 300000

[github-actions]

Findings

• None.

Questions

• None.

Summary
Review mode: initial

No high-confidence issues found in the added or modified lines. Static review covered the config/read handshake, value validation and fail-open behavior, and propagation through fresh, resumed, imported-fork, /compact, and /goal thread initialization paths. Residual testing gap: the new launcher test directly asserts fresh and resumed threads only; the specialized imported-fork, /compact, and /goal paths rely on the shared builder without path-specific assertions.

Testing

• Not run (automation; PR code treated as untrusted). GitHub integration passed; test was pending at review time.

HAPI Bot