feat(ai): switch OpenAI provider to responses API

[hwbrzzl]

Summary

• Switch the OpenAI text provider from Chat Completions to the Responses API for normal prompts, streaming, and tool calling.
• Reuse provider-scoped response state so OpenAI tool loops can continue with previous_response_id and only send tool outputs on follow-up requests.
• Inline text documents as prompt content while keeping binary documents as file attachments so OpenAI-compatible providers can handle mixed attachments more reliably.

Why

The OpenAI provider was still speaking the older Chat Completions shape, which meant Goravel could not match the Responses API behavior now expected by OpenAI-compatible backends. This updates the provider to send Responses input items, parse Responses output and stream events, and keep tool-call continuation aligned with previous_response_id so follow-up tool requests stay small and consistent.

resp, err := facades.AI().WithContext(ctx).Agent(agents.NewChatAgent())
if err != nil {
	return ctx.Response().Json(http.StatusInternalServerError, http.Json{
		"error": err.Error(),
	})
}

reply, err := resp.Prompt("What's the content of the attachments?", ai.WithAttachments(
	ai.ImageFromPath("logo.png"),
	ai.DocumentFromPath("123.txt"),
))
if err != nil {
	return ctx.Response().Json(http.StatusInternalServerError, http.Json{
		"error": err.Error(),
	})
}

return ctx.Response().Success().Json(http.Json{
	"reply": reply.Text(),
})

This also fixes two compatibility issues in real user flows. Before, tool loops had to rebuild growing request bodies instead of resuming from the prior OpenAI response, and plain-text documents such as 123.txt were uploaded as input_file, which some OpenAI-compatible providers reject unless the file is a PDF. After this change, tool continuations reuse provider state through AgentPrompt.ProviderState, and text-like documents are sent as prompt text while PDFs and other binary files continue to use file attachments.

// Before: plain text documents were always sent as file uploads.
resp, err := conv.Prompt("What's the content of the attachments?", ai.WithAttachments(
	ai.ImageFromPath("logo.png"),
	ai.DocumentFromPath("123.txt"),
))

// After: text documents are inlined as prompt text, while binary files remain file attachments.
resp, err := conv.Prompt("What's the content of the attachments?", ai.WithAttachments(
	ai.ImageFromPath("logo.png"),
	ai.DocumentFromPath("123.txt"),
	ai.DocumentFromPath("manual.pdf"),
))

[Copilot]

Pull request overview

This PR migrates the OpenAI text provider implementation from Chat Completions to the OpenAI Responses API, adding provider-scoped state to support smaller tool-loop follow-ups via previous_response_id, and improving attachment handling by inlining text-like documents as prompt text.

Changes:

• Add ProviderState to contracts/ai.AgentPrompt and implement a conversation-scoped, thread-safe provider state map.
• Update the OpenAI provider to build Responses API input items, parse Responses output (including tool calls), and stream via Responses SSE events.
• Update tests to validate Responses API request bodies, tool call behavior, and previous_response_id continuation.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
contracts/ai/provider.go	Adds ProviderState interface and threads it through AgentPrompt.
ai/provider_state.go	Implements a thread-safe map-backed provider state used by conversations.
ai/openai/response.go	Extends OpenAI response struct to track response IDs (used internally).
ai/openai/provider.go	Core migration to OpenAI Responses API (prompt, stream, tool calls, attachments, continuation).
ai/openai/provider_test.go	Updates prompt/stream tests to assert Responses API payloads and parsing.
ai/openai/provider_tool_test.go	Updates tool tests and adds coverage for previous_response_id in prompt/stream tool loops.
ai/conversation.go	Allocates and passes per-conversation ProviderState; resets state on Reset().
ai/conversation_test.go	Updates expected provider calls to include ProviderState.
ai/application_test.go	Updates expected prompt payloads to include ProviderState.

[codecov]

Codecov Report

❌ Patch coverage is 91.88192% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.36%. Comparing base (ecfbcc1) to head (daf059a).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
ai/openai/provider.go	91.48%	10 Missing and 6 partials ⚠️
database/gorm/query.go	33.33%	4 Missing ⚠️
database/db/utils.go	66.66%	0 Missing and 1 partial ⚠️
support/collect/collection.go	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1457      +/-   ##
==========================================
+ Coverage   69.29%   69.36%   +0.06%     
==========================================
  Files         364      365       +1     
  Lines       28713    28795      +82     
==========================================
+ Hits        19897    19973      +76     
- Misses       7924     7928       +4     
- Partials      892      894       +2     

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[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated 11 comments.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 3 comments.