fix(run,lanes): prompt autocomplete, per-lane Active runs, compact Changes header

- The run form's prompt box offers suggestions again: `/` lists the run
  cwd's project and user commands and skills plus the CLI built-ins
  (claude lanes only), `@` lists files under the cwd; Enter picks while
  the list is open and sends otherwise. The 2f39f4e rewrite had left a
  bare textarea that ignored both.
- Active runs lists only the current lane's runs and external sessions
  (sessions matched to the lane by longest path-boundary cwd), instead of
  every lane's.
- The Changes panel's git line and its actions are one compact row in one
  card, and the mode/range toolbar is one wrapping row.
- The lane card hides itself when it has nothing to show, instead of
  leaving an empty frame where the git row used to be.

client/src/lib/api.ts

@@ -482,6 +482,15 @@ export function dashboardToken(): string | null {
   }
 }
 
+/** `?scope=&cwd=` for the cc-config list endpoints, each part only when given. */
+function ccQuery(scope?: CcScope, cwd?: string): string {
+  const qs = new URLSearchParams();
+  if (scope) qs.set("scope", scope);
+  if (cwd) qs.set("cwd", cwd);
+  const q = qs.toString();
+  return q ? `?${q}` : "";
+}
+
 /**
  * Shared fetch wrapper used by every method on {@link api}. Prefixes `path`
  * with {@link BASE} ("/api"), attaches the dashboard auth token (if any) as
@@ -1390,10 +1399,11 @@ export const api = {
      * list endpoints below (`agents`, `commands`, `outputStyles`).
      *
      * @param scope Optional {@link CcScope} ("user"|"project"|"all") filter.
+     * @param cwd Project directory to read, instead of the server's own cwd.
      * @returns `{ items }` — the {@link CcMdItem} summaries for each skill.
      */
-    skills: (scope?: CcScope) =>
-      request<{ items: CcMdItem[] }>(`/cc-config/skills${scope ? `?scope=${scope}` : ""}`),
+    skills: (scope?: CcScope, cwd?: string) =>
+      request<{ items: CcMdItem[] }>(`/cc-config/skills${ccQuery(scope, cwd)}`),
     /**
      * GET /api/cc-config/agents - user and/or project subagent definitions.
      * @param scope Optional {@link CcScope} filter.
@@ -1404,10 +1414,11 @@ export const api = {
     /**
      * GET /api/cc-config/commands - user and/or project slash commands.
      * @param scope Optional {@link CcScope} filter.
+     * @param cwd Project directory to read, instead of the server's own cwd.
      * @returns `{ items }` — {@link CcMdItem} summaries for each command.
      */
-    commands: (scope?: CcScope) =>
-      request<{ items: CcMdItem[] }>(`/cc-config/commands${scope ? `?scope=${scope}` : ""}`),
+    commands: (scope?: CcScope, cwd?: string) =>
+      request<{ items: CcMdItem[] }>(`/cc-config/commands${ccQuery(scope, cwd)}`),
     /**
      * GET /api/cc-config/output-styles.
      * @param scope Optional {@link CcScope} filter.