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, 6 deletions

diff --git a/packages/core/src/models/registry.ts b/packages/core/src/models/registry.ts
index 9ea0b32..4a24a51 100644
--- a/packages/core/src/models/registry.ts
+++ b/packages/core/src/models/registry.ts
@@ -10,10 +10,7 @@ export class ModelRegistry {
 		this._initConfig(keys, new Map());
 	}
 
-	private _initConfig(
-		keys: KeyDefinition[],
-		existingStates: Map<string, KeyState>,
-	): void {
+	private _initConfig(keys: KeyDefinition[], existingStates: Map<string, KeyState>): void {
 		this.keyOrder = keys.map((k) => k.id);
 
 		const newStates = new Map<string, KeyState>();
@@ -83,8 +80,7 @@ export class ModelRegistry {
 		return this.keyOrder
 			.map((id) => this.keyStates.get(id))
 			.filter(
-				(state): state is KeyState =>
-					state !== undefined && state.definition.provider === provider,
+				(state): state is KeyState => state !== undefined && state.definition.provider === provider,
 			);
 	}
 }