fix(proxy): lift Codex additional_tools input carriers into chat tools

[525300887039]

Summary

Related to #466.

Codex requests reported with Desktop 26.901 / codex.exe 0.153.4 carry tools in
additional_tools input items. Those tools were not collected before proxy
conversion, leaving the upstream Chat model without the carried tools.

• Collect supported tools from direct additional_tools input items (array
  elements or the already-supported single input object) using the existing
  registry. Keep top-level priority, input order and first-definition dedup.
• Ignore the carrier's role/content in both converters: it must not become
  Chat messages or Anthropic system/messages. Preserve real messages and
  pending tool calls, media and reasoning.
• Do not interpret markers inside schemas, message content or tool outputs as
  declarations. Preserve the existing recursive tool_search_output behavior.

Adapted from farion1231/cc-switch#7454
(a35e5000b4ef809ed76eb36bd164bf6a35c36afc) with a direct-input boundary
guard and consistent carrier handling in both converters. Changes are limited to
src-tauri/src/proxy/providers/transform_codex_chat.rs and
src-tauri/src/proxy/providers/transform_codex_anthropic.rs.

Testing

Run from src-tauri/ with Rust 1.91.1 and isolated configuration directories:

• cargo test --lib --no-default-features additional_tools: 8 passed. The
  original omission, nested-marker regression and Anthropic content leak were
  demonstrated failing before their respective fixes. The new table-driven
  test checks four carrier roles with string/array content against both actual
  request converters, preserving the real instructions, user message and tools.
• Codex Chat / Anthropic conversion modules: 68 / 71 passed; streaming modules:
  19 / 20 passed. Tests cover registration order, dedup, history names,
  response restoration and unchanged pending state.
• cargo test --no-fail-fast: 4923 passed, 5 failed, 2 ignored across 44
  targets on the final patch (excluding a duplicated subprocess result).
  Only prompt_commands (2 editor-configuration tests) and provider_commands
  (3 official usage-template tests) failed; identical failures were reproduced
  on the unmodified baseline. This is not a passing full-suite result.
• cargo test --lib --no-default-features: 2077 passed, 0 failed, 2 ignored.
  CI unit commands: library 4363 passed, 2 ignored; binary 10 passed. The
  CI-selected proxy integration cases passed (forwarder, daemon, proxy_database).
• RUSTFLAGS="-D warnings" library-only check and compile-test, the CI direct
  dependency guard, both changed-file rustfmt --check runs and
  git diff --check passed. cargo clippy --lib --no-default-features passed
  with existing warnings.

Notes

• Namespace children remain limited to function; the namespace-nested
  custom tool in Proxy drops Codex tools sent as additional_tools input items — model receives no tools #466's capture is still unsupported. This is a partial
  compatibility fix, not a claim to resolve every reported tool shape.
• Unchanged by this patch: repo-wide cargo fmt --check fails in five files
  (21 hunks from feat(auth): support Codex rate limit reset credits in quota inspection and consumption #475), and default-feature cargo clippy fails with
  clippy::reversed_empty_ranges at src/cli/tui/ui/home_chart.rs:806.
• The existing session timestamp flakes were reproduced on the baseline during
  the earlier audit; they did not occur in this final run.
• No real Codex/upstream end-to-end run or local Windows validation. Carrier-
  specific SSE cases and the two ignored benchmark tests were not run.