Fix: use function apply_patch tool for Bedrock model

[celia-oai]

Why

openai.gpt-5.4-cmb is served through the Amazon Bedrock provider, whose request validator currently accepts function and mcp tool specs but rejects Responses custom tools. The CMB catalog entry reuses the bundled gpt-5.4 metadata, which marks apply_patch_tool_type as freeform. That causes Codex to include an apply_patch tool with type: "custom", so even heavily disabled sessions can fail before the model runs with:

Invalid tools: unknown variant `custom`, expected `function` or `mcp`

This is provider-specific: the model should still expose apply_patch, but for Bedrock it needs to use the JSON/function tool shape instead of the freeform/custom shape.

What Changed

• Override the openai.gpt-5.4-cmb static catalog entry to set apply_patch_tool_type to function after inheriting the rest of the gpt-5.4 model metadata.
• Update the catalog test expectation so the CMB entry continues to track gpt-5.4 metadata except for this Bedrock-specific tool shape override.

Verification

• cargo test -p codex-model-provider
• just fix -p codex-model-provider