Fix Windows embedding model cache and dashboard DB path resolution

- Set explicit cacheDir for @huggingface/transformers to
  ~/.local/share/opencode/storage/plugin/magic-context/models/ instead of
  relying on the library's default .cache inside node_modules. On Windows
  the npm cached install path is often inaccessible, causing 'Unable to get
  model file path or buffer' failures. Also survives plugin updates.
- Fix dashboard Rust DB path resolution on Windows: was using %APPDATA%
  (dirs::data_dir) but the plugin stores context.db at ~/.local/share
  on all platforms. Now both resolve_db_path and resolve_opencode_db_path
  use XDG_DATA_HOME or ~/.local/share unconditionally.

Closes #10

Author: ualtinok

packages/dashboard/src-tauri/src/db.rs

@@ -4,21 +4,17 @@ use std::collections::{HashMap, HashSet};
 use std::path::PathBuf;
 
 pub fn resolve_db_path() -> Option<PathBuf> {
-    // The magic-context plugin uses ~/.local/share/opencode/... on macOS and Linux
-    // (XDG-style), and %APPDATA%/opencode/... on Windows.
-    let data_dir = if cfg!(target_os = "windows") {
-        dirs::data_dir()?
-    } else {
-        // XDG_DATA_HOME or ~/.local/share (matches plugin behavior)
-        std::env::var("XDG_DATA_HOME")
-            .map(PathBuf::from)
-            .unwrap_or_else(|_| {
-                dirs::home_dir()
-                    .unwrap_or_default()
-                    .join(".local")
-                    .join("share")
-            })
-    };
+    // The magic-context plugin uses XDG_DATA_HOME or ~/.local/share on ALL platforms
+    // (see packages/plugin/src/shared/data-path.ts). On Windows this means
+    // C:\Users\<user>\.local\share — NOT %APPDATA%.
+    let data_dir = std::env::var("XDG_DATA_HOME")
+        .map(PathBuf::from)
+        .unwrap_or_else(|_| {
+            dirs::home_dir()
+                .unwrap_or_default()
+                .join(".local")
+                .join("share")
+        });
     let db_path = data_dir
         .join("opencode")
         .join("storage")
@@ -33,18 +29,15 @@ pub fn resolve_db_path() -> Option<PathBuf> {
 }
 
 pub fn resolve_opencode_db_path() -> Option<PathBuf> {
-    let data_dir = if cfg!(target_os = "windows") {
-        dirs::data_dir()?
-    } else {
-        std::env::var("XDG_DATA_HOME")
-            .map(PathBuf::from)
-            .unwrap_or_else(|_| {
-                dirs::home_dir()
-                    .unwrap_or_default()
-                    .join(".local")
-                    .join("share")
-            })
-    };
+    // OpenCode also uses XDG_DATA_HOME or ~/.local/share on all platforms.
+    let data_dir = std::env::var("XDG_DATA_HOME")
+        .map(PathBuf::from)
+        .unwrap_or_else(|_| {
+            dirs::home_dir()
+                .unwrap_or_default()
+                .join(".local")
+                .join("share")
+        });
     let db_path = data_dir.join("opencode").join("opencode.db");
     if db_path.exists() {
         Some(db_path)

packages/plugin/src/features/magic-context/memory/embedding-local.ts

@@ -1,4 +1,7 @@
+import { mkdirSync } from "node:fs";
+import { join } from "node:path";
 import { DEFAULT_LOCAL_EMBEDDING_MODEL } from "../../../config/schema/magic-context";
+import { getOpenCodeStorageDir } from "../../../shared/data-path";
 import { log } from "../../../shared/logger";
 import type { EmbeddingProvider } from "./embedding-provider";
 
@@ -155,11 +158,33 @@ export class LocalEmbeddingProvider implements EmbeddingProvider {
                     string,
                     unknown
                 >;
-                const env = transformersModule.env as { logLevel?: unknown };
+                const env = transformersModule.env as {
+                    logLevel?: unknown;
+                    cacheDir?: string;
+                };
                 const LogLevel = transformersModule.LogLevel as Record<string, unknown> | undefined;
                 if (LogLevel && "ERROR" in LogLevel) {
                     env.logLevel = LogLevel.ERROR;
                 }
+
+                // Set a stable model cache directory outside of node_modules.
+                // On Windows, the default .cache inside the npm cached install
+                // (e.g. ~\.cache\opencode\packages\...\node_modules\@huggingface\transformers\.cache)
+                // can be inaccessible or non-writable, causing "Unable to get model file path
+                // or buffer" failures. Using our own storage dir survives plugin updates too.
+                const modelCacheDir = join(
+                    getOpenCodeStorageDir(),
+                    "plugin",
+                    "magic-context",
+                    "models",
+                );
+                try {
+                    mkdirSync(modelCacheDir, { recursive: true });
+                    env.cacheDir = modelCacheDir;
+                } catch {
+                    // Non-fatal — fall back to library default if we can't create the dir
+                    log("[magic-context] could not create model cache dir, using library default");
+                }
                 const createPipeline = transformersModule.pipeline as CreateEmbeddingPipeline;
 
                 // Retry loop absorbs transient failures seen when multiple plugin