flatten: move poc-memory contents to workspace root

No more subcrate nesting — src/, agents/, schema/, defaults/, build.rs
all live at the workspace root. poc-daemon remains as the only workspace
member. Crate name (poc-memory) and all imports unchanged.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/api/openai.rs

@@ -0,0 +1,215 @@
+// api/openai.rs — OpenAI-compatible backend
+//
+// Works with any provider that implements the OpenAI chat completions
+// API: OpenRouter, vLLM, llama.cpp, Fireworks, Together, etc.
+// Also used for local models (Qwen, llama) via compatible servers.
+
+use anyhow::Result;
+use reqwest::Client;
+use std::time::Duration;
+
+use crate::agent::types::*;
+use crate::agent::ui_channel::{StreamTarget, UiMessage, UiSender};
+
+pub async fn stream(
+    client: &Client,
+    base_url: &str,
+    api_key: &str,
+    model: &str,
+    messages: &[Message],
+    tools: Option<&[ToolDef]>,
+    ui_tx: &UiSender,
+    target: StreamTarget,
+    reasoning_effort: &str,
+    temperature: Option<f32>,
+) -> Result<(Message, Option<Usage>)> {
+    let request = ChatRequest {
+        model: model.to_string(),
+        messages: messages.to_vec(),
+        tool_choice: tools.map(|_| "auto".to_string()),
+        tools: tools.map(|t| t.to_vec()),
+        max_tokens: Some(16384),
+        temperature: Some(temperature.unwrap_or(0.6)),
+        stream: Some(true),
+        reasoning: if reasoning_effort != "none" && reasoning_effort != "default" {
+            Some(ReasoningConfig {
+                enabled: true,
+                effort: Some(reasoning_effort.to_string()),
+            })
+        } else {
+            None
+        },
+        chat_template_kwargs: None,
+    };
+
+    let url = format!("{}/chat/completions", base_url);
+    let msg_count = request.messages.len();
+    let debug_label = format!("{} messages, model={}", msg_count, model);
+
+    let mut response = super::send_and_check(
+        client,
+        &url,
+        &request,
+        ("Authorization", &format!("Bearer {}", api_key)),
+        &[],
+        ui_tx,
+        &debug_label,
+    )
+    .await?;
+
+    let mut reader = super::SseReader::new(ui_tx);
+
+    let mut content = String::new();
+    let mut tool_calls: Vec<ToolCall> = Vec::new();
+    let mut usage = None;
+    let mut finish_reason = None;
+    let mut reasoning_chars: usize = 0;
+    let mut empty_deltas: u64 = 0;
+    let mut first_content_at: Option<Duration> = None;
+
+    let _reasoning_enabled = reasoning_effort != "none";
+
+    while let Some(event) = reader.next_event(&mut response).await? {
+        // OpenRouter sometimes embeds error objects in the stream
+        if let Some(err_msg) = event["error"]["message"].as_str() {
+            let raw = event["error"]["metadata"]["raw"].as_str().unwrap_or("");
+            let _ = ui_tx.send(UiMessage::Debug(format!(
+                "API error in stream: {}",
+                err_msg
+            )));
+            anyhow::bail!("API error in stream: {} {}", err_msg, raw);
+        }
+
+        let chunk: ChatCompletionChunk = match serde_json::from_value(event.clone()) {
+            Ok(c) => c,
+            Err(e) => {
+                // Log unparseable events — they may contain error info
+                let preview = event.to_string();
+                let _ = ui_tx.send(UiMessage::Debug(format!(
+                    "unparseable SSE event ({}): {}",
+                    e, &preview[..preview.len().min(300)]
+                )));
+                continue;
+            }
+        };
+
+        if chunk.usage.is_some() {
+            usage = chunk.usage;
+        }
+
+        for choice in &chunk.choices {
+            if choice.finish_reason.is_some() {
+                finish_reason = choice.finish_reason.clone();
+            }
+
+            let has_content = choice.delta.content.is_some();
+            let has_tools = choice.delta.tool_calls.is_some();
+
+            // Reasoning tokens — multiple field names across providers
+            let mut has_reasoning = false;
+            if let Some(ref r) = choice.delta.reasoning_content {
+                reasoning_chars += r.len();
+                has_reasoning = true;
+                if !r.is_empty() {
+                    let _ = ui_tx.send(UiMessage::Reasoning(r.clone()));
+                }
+            }
+            if let Some(ref r) = choice.delta.reasoning {
+                reasoning_chars += r.len();
+                has_reasoning = true;
+                if !r.is_empty() {
+                    let _ = ui_tx.send(UiMessage::Reasoning(r.clone()));
+                }
+            }
+            if let Some(ref r) = choice.delta.reasoning_details {
+                let s = r.to_string();
+                reasoning_chars += s.len();
+                has_reasoning = true;
+                if !s.is_empty() && s != "null" {
+                    let _ = ui_tx.send(UiMessage::Reasoning(s));
+                }
+            }
+
+            if let Some(ref text_delta) = choice.delta.content {
+                if first_content_at.is_none() && !text_delta.is_empty() {
+                    first_content_at = Some(reader.stream_start.elapsed());
+                    let _ = ui_tx.send(UiMessage::Activity("streaming...".into()));
+                }
+                content.push_str(text_delta);
+                let _ = ui_tx.send(UiMessage::TextDelta(text_delta.clone(), target));
+            }
+
+            if let Some(ref tc_deltas) = choice.delta.tool_calls {
+                for tc_delta in tc_deltas {
+                    let idx = tc_delta.index;
+                    while tool_calls.len() <= idx {
+                        tool_calls.push(ToolCall {
+                            id: String::new(),
+                            call_type: "function".to_string(),
+                            function: FunctionCall {
+                                name: String::new(),
+                                arguments: String::new(),
+                            },
+                        });
+                    }
+                    if let Some(ref id) = tc_delta.id {
+                        tool_calls[idx].id = id.clone();
+                    }
+                    if let Some(ref ct) = tc_delta.call_type {
+                        tool_calls[idx].call_type = ct.clone();
+                    }
+                    if let Some(ref func) = tc_delta.function {
+                        if let Some(ref name) = func.name {
+                            tool_calls[idx].function.name = name.clone();
+                        }
+                        if let Some(ref args) = func.arguments {
+                            tool_calls[idx].function.arguments.push_str(args);
+                        }
+                    }
+                }
+            }
+
+            if !has_reasoning && !has_content && !has_tools && choice.finish_reason.is_none() {
+                empty_deltas += 1;
+            }
+        }
+    }
+
+    let total_elapsed = reader.stream_start.elapsed();
+
+    super::log_diagnostics(
+        ui_tx,
+        content.len(),
+        tool_calls.len(),
+        reasoning_chars,
+        reasoning_effort,
+        &finish_reason,
+        reader.chunks_received,
+        reader.sse_lines_parsed,
+        reader.sse_parse_errors,
+        empty_deltas,
+        total_elapsed,
+        first_content_at,
+        &usage,
+        &tool_calls,
+    );
+
+    // Model/provider error delivered inside the stream (HTTP 200 but
+    // finish_reason="error"). Surface whatever content came back as
+    // the error message so the caller can retry or display it.
+    // Don't append the trailing newline — this isn't real content.
+    if finish_reason.as_deref() == Some("error") {
+        let detail = if content.is_empty() {
+            "no details".to_string()
+        } else {
+            content
+        };
+        anyhow::bail!("model stream error: {}", detail);
+    }
+
+    if !content.is_empty() {
+        let _ = ui_tx.send(UiMessage::TextDelta("\n".to_string(), target));
+    }
+
+    Ok((super::build_response_message(content, tool_calls), usage))
+}