Decouple sidecar versioning from app versioning

Sidecar now has its own version (1.0.0) and release lifecycle:
- Sidecar tags: sidecar-v1.0.0, sidecar-v1.0.1, etc.
- App tags: v0.2.x (unchanged)
- Sidecar workflow triggers only on python/** changes or manual dispatch
- App release no longer bumps python/pyproject.toml

Sidecar version tracked via sidecar-version.txt in app data dir:
- resolve_sidecar_path() reads version from file instead of CARGO_PKG_VERSION
- download_sidecar() fetches latest sidecar-v* release from Gitea API
- check_sidecar_update() compares local vs remote sidecar versions
- Version file written after successful download

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src-tauri/src/commands/sidecar.rs

@@ -20,19 +20,81 @@ pub struct UpdateInfo {
     pub latest_version: String,
 }
 
-/// Check if the sidecar binary exists for the current version.
+/// Read the locally installed sidecar version from `sidecar-version.txt`.
+/// Returns `None` if the file doesn't exist or can't be read.
+fn read_local_sidecar_version() -> Option<String> {
+    let data_dir = DATA_DIR.get()?;
+    let version_file = data_dir.join("sidecar-version.txt");
+    std::fs::read_to_string(version_file)
+        .ok()
+        .map(|v| v.trim().to_string())
+        .filter(|v| !v.is_empty())
+}
+
+/// Write the sidecar version to `sidecar-version.txt` after a successful download.
+fn write_local_sidecar_version(version: &str) -> Result<(), String> {
+    let data_dir = DATA_DIR.get().ok_or("App data directory not initialized")?;
+    let version_file = data_dir.join("sidecar-version.txt");
+    std::fs::write(&version_file, version)
+        .map_err(|e| format!("Failed to write sidecar version file: {}", e))
+}
+
+/// Fetch releases from the Gitea API and find the latest sidecar release
+/// (one whose tag_name starts with "sidecar-v").
+async fn fetch_latest_sidecar_release(
+    client: &reqwest::Client,
+) -> Result<serde_json::Value, String> {
+    let releases_url = format!("{}/releases?limit=20", REPO_API);
+    let resp = client
+        .get(&releases_url)
+        .header("Accept", "application/json")
+        .send()
+        .await
+        .map_err(|e| format!("Failed to fetch releases: {}", e))?;
+
+    if !resp.status().is_success() {
+        return Err(format!("Failed to fetch releases: HTTP {}", resp.status()));
+    }
+
+    let releases = resp
+        .json::<Vec<serde_json::Value>>()
+        .await
+        .map_err(|e| format!("Failed to parse releases JSON: {}", e))?;
+
+    releases
+        .into_iter()
+        .find(|r| {
+            r["tag_name"]
+                .as_str()
+                .map_or(false, |t| t.starts_with("sidecar-v"))
+        })
+        .ok_or_else(|| "No sidecar release found".to_string())
+}
+
+/// Extract the version string from a sidecar tag name (e.g. "sidecar-v1.0.1" -> "1.0.1").
+fn version_from_sidecar_tag(tag: &str) -> &str {
+    tag.strip_prefix("sidecar-v").unwrap_or(tag)
+}
+
+/// Check if the sidecar binary exists for the currently installed version.
 #[tauri::command]
 pub fn check_sidecar() -> bool {
     let data_dir = match DATA_DIR.get() {
         Some(d) => d,
         None => return false,
     };
+
+    let version = match read_local_sidecar_version() {
+        Some(v) => v,
+        None => return false,
+    };
+
     let binary_name = if cfg!(target_os = "windows") {
         "voice-to-notes-sidecar.exe"
     } else {
         "voice-to-notes-sidecar"
     };
-    let version = env!("CARGO_PKG_VERSION");
+
     let extract_dir = data_dir.join(format!("sidecar-{}", version));
     extract_dir.join(binary_name).exists()
 }
@@ -61,44 +123,35 @@ fn platform_arch() -> &'static str {
 #[tauri::command]
 pub async fn download_sidecar(app: AppHandle, variant: String) -> Result<(), String> {
     let data_dir = DATA_DIR.get().ok_or("App data directory not initialized")?;
-    let version = env!("CARGO_PKG_VERSION");
 
     let os = platform_os();
     let arch = platform_arch();
     let asset_name = format!("sidecar-{}-{}-{}.zip", os, arch, variant);
 
-    // Fetch release info from Gitea API to get the download URL
-    let release_url = format!("{}/releases/tags/v{}", REPO_API, version);
+    // Fetch the latest sidecar release from Gitea API
     let client = reqwest::Client::new();
-    let release_resp = client
-        .get(&release_url)
-        .header("Accept", "application/json")
-        .send()
-        .await
-        .map_err(|e| format!("Failed to fetch release info: {}", e))?;
+    let sidecar_release = fetch_latest_sidecar_release(&client).await?;
 
-    if !release_resp.status().is_success() {
-        return Err(format!(
-            "Failed to fetch release info: HTTP {}",
-            release_resp.status()
-        ));
-    }
-
-    let release_json = release_resp
-        .json::<serde_json::Value>()
-        .await
-        .map_err(|e| format!("Failed to parse release JSON: {}", e))?;
+    let tag = sidecar_release["tag_name"]
+        .as_str()
+        .ok_or("No tag_name in sidecar release")?;
+    let sidecar_version = version_from_sidecar_tag(tag).to_string();
 
     // Find the matching asset
-    let assets = release_json["assets"]
+    let assets = sidecar_release["assets"]
         .as_array()
-        .ok_or("No assets found in release")?;
+        .ok_or("No assets found in sidecar release")?;
 
     let download_url = assets
         .iter()
         .find(|a| a["name"].as_str() == Some(&asset_name))
         .and_then(|a| a["browser_download_url"].as_str())
-        .ok_or_else(|| format!("Asset '{}' not found in release v{}", asset_name, version))?
+        .ok_or_else(|| {
+            format!(
+                "Asset '{}' not found in sidecar release {}",
+                asset_name, tag
+            )
+        })?
         .to_string();
 
     // Stream download with progress events
@@ -121,8 +174,7 @@ pub async fn download_sidecar(app: AppHandle, variant: String) -> Result<(), Str
         .map_err(|e| format!("Failed to create zip file: {}", e))?;
 
     while let Some(chunk) = stream.next().await {
-        let chunk: bytes::Bytes =
-            chunk.map_err(|e| format!("Download stream error: {}", e))?;
+        let chunk: bytes::Bytes = chunk.map_err(|e| format!("Download stream error: {}", e))?;
         file.write_all(&chunk)
             .map_err(|e| format!("Failed to write chunk: {}", e))?;
         downloaded += chunk.len() as u64;
@@ -142,7 +194,7 @@ pub async fn download_sidecar(app: AppHandle, variant: String) -> Result<(), Str
     }
 
     // Extract the downloaded zip
-    let extract_dir = data_dir.join(format!("sidecar-{}", version));
+    let extract_dir = data_dir.join(format!("sidecar-{}", sidecar_version));
     SidecarManager::extract_zip(&zip_path, &extract_dir)?;
 
     // Make the binary executable on Unix
@@ -157,9 +209,12 @@ pub async fn download_sidecar(app: AppHandle, variant: String) -> Result<(), Str
         }
     }
 
+    // Write the sidecar version file
+    write_local_sidecar_version(&sidecar_version)?;
+
     // Clean up the zip file and old sidecar versions
     let _ = std::fs::remove_file(&zip_path);
-    SidecarManager::cleanup_old_sidecars(data_dir, version);
+    SidecarManager::cleanup_old_sidecars(data_dir, &sidecar_version);
 
     Ok(())
 }
@@ -172,36 +227,19 @@ pub async fn check_sidecar_update() -> Result<Option<UpdateInfo>, String> {
         return Ok(None);
     }
 
-    let current_version = env!("CARGO_PKG_VERSION").to_string();
+    let current_version = match read_local_sidecar_version() {
+        Some(v) => v,
+        None => return Ok(None),
+    };
 
-    // Fetch latest release from Gitea API
-    let latest_url = format!("{}/releases/latest", REPO_API);
+    // Fetch latest sidecar release from Gitea API
     let client = reqwest::Client::new();
-    let resp = client
-        .get(&latest_url)
-        .header("Accept", "application/json")
-        .send()
-        .await
-        .map_err(|e| format!("Failed to fetch latest release: {}", e))?;
+    let sidecar_release = fetch_latest_sidecar_release(&client).await?;
 
-    if !resp.status().is_success() {
-        return Err(format!(
-            "Failed to fetch latest release: HTTP {}",
-            resp.status()
-        ));
-    }
-
-    let release_json = resp
-        .json::<serde_json::Value>()
-        .await
-        .map_err(|e| format!("Failed to parse release JSON: {}", e))?;
-
-    let latest_tag = release_json["tag_name"]
+    let latest_tag = sidecar_release["tag_name"]
         .as_str()
-        .ok_or("No tag_name in release")?;
-
-    // Strip leading 'v' if present
-    let latest_version = latest_tag.strip_prefix('v').unwrap_or(latest_tag);
+        .ok_or("No tag_name in sidecar release")?;
+    let latest_version = version_from_sidecar_tag(latest_tag);
 
     if latest_version != current_version {
         Ok(Some(UpdateInfo {