feat: agent builder, CWD support, auto-save, UI polish, unavailable tool handling

- Agent Builder: full CRUD with card grid, drag-and-drop model reorder, edit/delete
- Auto-save on edit with 600ms debounce, AbortController for concurrency, fieldset disabled until name entered
- Agent definitions stored as TOML with cwd field, loaded from global/project dirs
- Working directory: per-tab CWD override in Chat Settings, agent default CWD, auto-create on first message
- CWD validation: check-dir endpoint with ~ expansion, real-time validity indicator
- Subagent CWD validated against parent's effective CWD using path.relative
- Unavailable tool calls: caught gracefully, shown as tool call with error badge, model retries
- UI: tab bar border radius, sidebar border removed, chat input ghost style, scroll-to-bottom rectangle
- Skills dir collapse uses CSS rotation, Model Choice renamed to Chat Settings, System Prompt view removed
- Reusable SkillsBrowser/ToolPermissions with external mode for Agent Builder
- ModelSelector: Agent/Manual toggle, agent list, Agent Settings link
- Page router, skills recursive scanning, bin/up gopass removed, docker volume mounts

1 files changed, 2 insertions, 2 deletions

diff --git a/packages/frontend/src/lib/components/ChatInput.svelte b/packages/frontend/src/lib/components/ChatInput.svelte
index 8910bb4..21c85fe 100644
--- a/packages/frontend/src/lib/components/ChatInput.svelte
+++ b/packages/frontend/src/lib/components/ChatInput.svelte
@@ -24,13 +24,13 @@ function submit() {
 }
 </script>
 
-<div class="flex items-center gap-2 p-3 border-t border-base-300 bg-base-100">
+<div class="flex items-center gap-2 p-3">
 	<input
 		bind:this={inputEl}
 		bind:value={inputValue}
 		type="text"
 		placeholder="Type a message..."
-		class="input flex-1"
+		class="input input-ghost flex-1"
 		onkeydown={handleKeydown}
 	/>
 	<button