Status LEDs, image model selection, backup restore, provider test, monthly versions

- Sidebar: three status LEDs (server, models, MCP) with an overview popover (/api/status)
- Images: preview stage, purpose-based model choice and reference images
  (Nano Banana Pro edit refines the chosen preview)
- Settings: restore a stored or uploaded backup (staged, applied on restart)
- Provider form: test connection; saving or reloading re-checks the status at once
- opencode Zen/Go: send x-opencode-session with a stable id per conversation
- Releases are named vYYYYMM-NNNNN; scripts/release.sh numbers, tags, builds and publishes
- Fix: backups made in the same second no longer overwrite each other

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/src/provider/anthropic.rs

@@ -168,7 +168,8 @@ impl Provider for Anthropic {
         for (k, v) in &req.model.options {
             body[k] = v.clone();
         }
-        let resp = self.request(reqwest::Method::POST, "/messages").json(&body).send().await?;
+        let rb = self.request(reqwest::Method::POST, "/messages").json(&body);
+        let resp = self.ep.with_session(rb, req.session_id.as_deref()).send().await?;
         if !resp.status().is_success() {
             return Err(http_error(resp).await);
         }

core/src/provider/mod.rs

@@ -30,6 +30,9 @@ pub struct ChatRequest {
     pub max_tokens: u64,
     /// Enable extended thinking / reasoning when the model supports it.
     pub reasoning: bool,
+    /// Stable id of the conversation; sent to gateways that route by session
+    /// (opencode: `x-opencode-session`) for routing and prompt caching.
+    pub session_id: Option<String>,
 }
 
 #[derive(Debug, Clone)]
@@ -84,6 +87,16 @@ impl Endpoint {
         }
     }
 
+    /// Session header for gateways that need one (opencode Zen/Go reject requests without it).
+    pub fn with_session(&self, rb: reqwest::RequestBuilder, session_id: Option<&str>) -> reqwest::RequestBuilder {
+        match session_id {
+            Some(id) if self.base_url.contains("opencode.ai") && !self.headers.keys().any(|k| k.eq_ignore_ascii_case("x-opencode-session")) => {
+                rb.header("x-opencode-session", id)
+            }
+            _ => rb,
+        }
+    }
+
     pub fn apply(&self, mut rb: reqwest::RequestBuilder) -> reqwest::RequestBuilder {
         if !self.api_key.is_empty() {
             rb = rb.header(&self.auth_header, format!("{}{}", self.auth_prefix, self.api_key));
@@ -99,7 +112,7 @@ impl Endpoint {
 pub fn http_client() -> reqwest::Client {
     reqwest::Client::builder()
         .connect_timeout(std::time::Duration::from_secs(20))
-        .user_agent(concat!("codecraft/", env!("CARGO_PKG_VERSION")))
+        .user_agent(format!("codecraft/{}", crate::version::VERSION))
         .build()
         .expect("http client")
 }
@@ -128,3 +141,27 @@ pub async fn http_error(resp: reqwest::Response) -> anyhow::Error {
         .unwrap_or_else(|| body.chars().take(500).collect());
     anyhow!("provider returned HTTP {status}: {detail}")
 }
+
+#[cfg(test)]
+mod session_header_tests {
+    use super::*;
+
+    fn ep(base: &str) -> Endpoint {
+        Endpoint { base_url: base.into(), api_key: String::new(), auth_header: "Authorization".into(), auth_prefix: "Bearer ".into(), headers: BTreeMap::new() }
+    }
+
+    fn header(ep: &Endpoint, id: Option<&str>) -> Option<String> {
+        let rb = ep.with_session(reqwest::Client::new().post(format!("{}/chat/completions", ep.base_url)), id);
+        rb.build().unwrap().headers().get("x-opencode-session").map(|v| v.to_str().unwrap().to_string())
+    }
+
+    #[test]
+    fn opencode_gets_the_session_header() {
+        assert_eq!(header(&ep("https://opencode.ai/zen/go/v1"), Some("s1")).as_deref(), Some("s1"));
+        assert_eq!(header(&ep("https://opencode.ai/zen/go/v1"), None), None);
+        assert_eq!(header(&ep("https://api.openai.com/v1"), Some("s1")), None);
+        let mut custom = ep("https://opencode.ai/zen/v1");
+        custom.headers.insert("X-Opencode-Session".into(), "fixed".into());
+        assert_eq!(header(&custom, Some("s1")), None, "a configured header wins");
+    }
+}

core/src/provider/openai.rs

@@ -198,7 +198,7 @@ impl Provider for OpenAi {
             body[k] = v.clone();
         }
         let rb = self.client.post(format!("{}/chat/completions", self.ep.base_url)).json(&body);
-        let resp = self.ep.apply(rb).send().await?;
+        let resp = self.ep.with_session(self.ep.apply(rb), req.session_id.as_deref()).send().await?;
         if !resp.status().is_success() {
             return Err(http_error(resp).await);
         }