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.

server/__tests__/pty-run.test.js

@@ -477,20 +477,21 @@ describe("pty-run", () => {
       }
     });
 
-    it("builds each prompt mode, with fixed args first", () => {
+    it("builds each prompt mode, with fixed args first, a dash-led prompt never a flag", () => {
       const argvFor = (tool, extra = {}) =>
         paneArgv(
           captureNewSession(() =>
             pty.spawnRun({ laneId: 15, cwd: "/tmp/repo", tool, initialPrompt: "-x y", ...extra })
           )
         );
-      assert.deepEqual(argvFor("gemini"), [at("gemini"), "--prompt-interactive", "-x y"]);
+      assert.deepEqual(argvFor("gemini"), [at("gemini"), "--prompt-interactive", " -x y"]);
+      // Behind a `--` separator the prompt is already a positional, kept as typed.
       assert.deepEqual(argvFor("grok"), [at("grok"), "--", "-x y"]);
-      assert.deepEqual(argvFor("command-code"), [at("command-code"), "--trust", "-x y"]);
+      assert.deepEqual(argvFor("command-code"), [at("command-code"), "--trust", " -x y"]);
       assert.deepEqual(argvFor("gemini", { bypass: false }), [
         at("gemini"),
         "--prompt-interactive",
-        "-x y",
+        " -x y",
       ]);
     });