fix(dashboard): include ~/.opencode/bin in opencode binary lookup

The Rust `get_available_models` command spawns `opencode models` to
populate the model picker for historian / dreamer / sidekick primary
and fallback dropdowns. GUI processes on macOS don't inherit shell
PATH, so the command tries an explicit list of candidate binary paths.

The previous candidate list missed the most important one: the official
OpenCode installer (`curl -fsSL https://opencode.ai/install | bash`)
writes the binary to `~/.opencode/bin/opencode`, NOT to ~/.local/bin
or anywhere else in the previous candidate list. Users with a stock
OpenCode install therefore got an empty `models()` array in the
dashboard, which made every model dropdown render the `<For fallback>`
empty-state ("No models found").

This bug masqueraded as a `fallback_models` filter problem in v0.3.3
because the user-visible symptom was the same — but the v0.3.3 fix
(string-vs-array normalization in the dropdown filter) only addressed
one of two distinct empty-dropdown causes. This commit fixes the
deeper one: `models()` itself was empty.

Promoted `~/.opencode/bin/opencode` to the first candidate on macOS
and Linux. Also added `%USERPROFILE%\.opencode\bin\opencode.exe` as
the first Windows candidate for symmetry. The shell-PATH `opencode`
fallback remains for users who launch OpenCode from a terminal.

After upgrade, the existing `availableModels` localStorage cache
(empty `[]` from a prior failed lookup) is overwritten by the next
`onMount` refresh, so users will see populated dropdowns on first
launch of the upgraded build with no manual cache clear required.

Verified: cargo check clean, dashboard frontend build clean.

Author: ualtinok

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

@@ -355,16 +355,32 @@ pub fn save_project_config(project_path: String, content: String) -> Result<(),
 
 #[tauri::command]
 pub async fn get_available_models() -> Vec<String> {
-    // GUI apps on macOS don't inherit shell PATH; try common locations
+    // GUI apps on macOS don't inherit shell PATH; try common locations.
+    //
+    // The first candidate must be `~/.opencode/bin/opencode` because that's
+    // the path the official OpenCode installer (`curl -fsSL ... | bash`)
+    // writes to and it's NOT on the GUI launcher's $PATH on macOS. Without
+    // this candidate, every dashboard model dropdown silently returned
+    // empty for users with a stock OpenCode install — the historian /
+    // dreamer / sidekick fallback "Add fallback model" dropdown would show
+    // "No models found" because `props.models = []`, so `grouped()`
+    // returned no groups and the `<For fallback>` rendered.
+    //
+    // Additional fallback paths cover pre-CI installs, custom installs,
+    // Homebrew on Intel + ARM, and shell-PATH discovery for users who
+    // launched OpenCode from a terminal.
     let candidates = if cfg!(target_os = "windows") {
-        vec!["opencode".to_string()]
+        let home = std::env::var("USERPROFILE").unwrap_or_default();
+        vec![
+            format!("{}\\.opencode\\bin\\opencode.exe", home),
+            "opencode".to_string(),
+        ]
     } else {
+        let home = std::env::var("HOME").unwrap_or_default();
         vec![
+            format!("{}/.opencode/bin/opencode", home),
             "opencode".to_string(),
-            format!(
-                "{}/.local/bin/opencode",
-                std::env::var("HOME").unwrap_or_default()
-            ),
+            format!("{}/.local/bin/opencode", home),
             "/usr/local/bin/opencode".to_string(),
             "/opt/homebrew/bin/opencode".to_string(),
         ]