chat: rename claude_sessions → general_chat_sessions; drop dead chat_sessions

The default /chat working directory is used by both the Claude and OpenCode harnesses
now, so its Claude-specific name was misleading.

- Rename the dir + accessors: getClaudeSessionsCwd → getGeneralChatSessionsCwd,
  ensureClaudeSessionsCwd → ensureGeneralChatSessionsCwd, path segment claude_sessions
  → general_chat_sessions (data-path on disk + code + UI labels/comments). No history
  migration — the old Claude transcript slug is orphaned (intentionally).

- Remove the vestigial chat_sessions dir (leftover from the retired session store):
  it only ever held empty claude/archived/ dirs, recreated by a signin hook. Drop that
  hook (+ its dead imports) and the 4 unused data-path accessors (getUserSessionsDir,
  getClaudeDir, getSessionDir, getArchivedSessionDir), and delete the dir.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/workspaces/state/src/useClaudeSessions.ts

@@ -19,13 +19,20 @@ export type ClaudeSessionSummary = {
 export type ClaudeSessionMessage =
   | { role: 'user'; text: string }
   | { role: 'assistant'; id: string; text: string }
-  | { role: 'tool'; toolName: string; toolInput: Record<string, unknown>; toolCallId: string; output?: string; isError?: boolean };
+  | {
+      role: 'tool';
+      toolName: string;
+      toolInput: Record<string, unknown>;
+      toolCallId: string;
+      output?: string;
+      isError?: boolean;
+    };
 
 export type ClaudeSessionDetail = { id: string; model: string; cwd: string; messages: ClaudeSessionMessage[] };
 
 export type ClaudePwd = { cwd: string; sessionCount: number; updatedAt: string; isDefault: boolean };
 
-// Query string for the selected working directory (null/undefined = the default claude_sessions dir).
+// Query string for the selected working directory (null/undefined = the default general_chat_sessions dir).
 const cwdQuery = (cwd?: string | null) => (cwd ? `?cwd=${encodeURIComponent(cwd)}` : '');
 
 /** The default /chat dir plus every directory that already has Claude sessions. */