feat(ui): a Claude-Desktop-style home for every workspace

/workspace?lane=<id> opens on the workspace's home (WorkspaceHome): a prompt
box whose Start opens a new session in the first free pane slot, Recents (a
live session attaches its pane, any other opens its transcript, nothing
resumes), and Instructions / Memory / Context / Folder. Instructions live in
lanes.instructions, extra folders and uploaded files in the new lane_sources
table (copies under <data dir>/workspace-context/<lane id>/); spawnRun reads
them from the lane's rows and hands Claude --add-dir + an appended system
prompt file, Codex --add-dir + developer_instructions. Memory is read-only.

Every dashboard pane carries AGENTHUB_RUN_ID; hooks forward it and the run
records which session the pane holds (a Claude pane follows /clear and
/resume but not a nested claude -p), so the sidebar and notifications open
the right pane (&run=). Settings loses its Projects group; Worktrees now
decides which worktrees Add folder suggests.

client/src/lib/api.ts

@@ -2739,6 +2739,37 @@ export const api = {
      * @param patch Subset of lane fields to update.
      * @returns `{ lane }` — the updated {@link Lane}.
      */
+    /** GET /api/lanes/:id/sources — the workspace's instructions, extra
+     *  folders and context files, and whether its tool can take them. */
+    sources: (id: number) => request<LaneSourcesView>(`/lanes/${id}/sources`),
+    /** PUT /api/lanes/:id/instructions — appended to every new pane's system prompt. */
+    setInstructions: (id: number, instructions: string | null) =>
+      request<LaneSourcesView>(`/lanes/${id}/instructions`, {
+        method: "PUT",
+        body: JSON.stringify({ instructions }),
+      }),
+    /** POST /api/lanes/:id/sources/folder — an extra folder the agent may use. */
+    addFolder: (id: number, path: string) =>
+      request<LaneSourcesView>(`/lanes/${id}/sources/folder`, {
+        method: "POST",
+        body: JSON.stringify({ path }),
+      }),
+    /** POST /api/lanes/:id/sources/file — upload one context file (≤ 10 MB). */
+    addFile: (id: number, file: File) =>
+      request<LaneSourcesView>(`/lanes/${id}/sources/file`, {
+        method: "POST",
+        body: file,
+        headers: {
+          "Content-Type": "application/octet-stream",
+          "X-File-Name": encodeURIComponent(file.name),
+        },
+      }),
+    /** DELETE /api/lanes/:id/sources/:sourceId — a folder stays on disk; an
+     *  uploaded file's AgentHub copy is deleted. */
+    removeSource: (id: number, sourceId: number) =>
+      request<LaneSourcesView>(`/lanes/${id}/sources/${sourceId}`, { method: "DELETE" }),
+    /** GET /api/lanes/:id/memory — CLAUDE.md/AGENTS.md and Claude's auto memory, read-only. */
+    memory: (id: number) => request<{ files: LaneMemoryFile[] }>(`/lanes/${id}/memory`),
     update: (id: number, patch: Partial<Lane>) =>
       request<{ lane: Lane }>(`/lanes/${id}`, { method: "PATCH", body: JSON.stringify(patch) }),
     /**
@@ -3879,6 +3910,38 @@ export interface RunHandle {
   tool: LaneTool;
 }
 
+/** One extra folder or uploaded context file of a workspace. */
+export interface LaneSource {
+  id: number;
+  kind: "folder" | "file";
+  path: string;
+  name: string;
+  size: number | null;
+  added_at: string;
+  /** The folder or file is gone from disk; it is skipped at spawn. */
+  missing: boolean;
+}
+
+/** Response shape of GET /api/lanes/:id/sources (and of every sources write). */
+export interface LaneSourcesView {
+  instructions: string;
+  /** The workspace's tool can take folders and instructions (claude, codex). */
+  supported: boolean;
+  maxFileBytes: number;
+  maxInstructions: number;
+  sources: LaneSource[];
+}
+
+/** One read-only memory file from GET /api/lanes/:id/memory. */
+export interface LaneMemoryFile {
+  label: string;
+  path: string;
+  size: number;
+  mtime: string;
+  truncated: boolean;
+  content: string;
+}
+
 /** Response shape of GET /api/run. */
 export interface RunListResponse {
   items: RunHandle[];