feat(opencode): leader keybind, explicit unmount on switch, non-wrapping indicator

Three improvements taken from reading the sibling opencode branches
(feat/opencode-extension-abhishek in particular):

- `<leader>m` opens the project picker. Switching is the repeated action and
  typing `/mcpctl` every time is friction; the other two commands stay
  palette-only.

- A switch disconnects before re-adding. `mcp.add` under the same name does
  re-point the tools on its own, but leaves it to opencode whether the previous
  client is closed — and an abandoned one keeps its `mcp-session-id` alive on
  mcplocal, which is exactly what holds a gated project open. Best-effort, so a
  first mount still works.

- The footer label renders `wrapMode="none" truncate`. The home prompt row is
  narrow enough that the default wrap broke `mcpctl:homeautomation` across two
  lines mid-word; clipping the tail of a long name reads far better.

Verified against opencode 1.18.15: ctrl-x m opens the picker, the home footer is
now one line, and a disconnect-then-add switch still lands — the model called
`mcpctl_begin_session` and listed the new project's tools.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BVwuCjuMoA13gmzYEfcrNP

src/cli/tests/config/opencode-extension-embed.test.ts

@@ -67,6 +67,22 @@ describe('embedded opencode plugins', () => {
     expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain("'--agent', 'opencode'");
   });
 
+  it('bind the switcher to a chord as well as a slash command', () => {
+    // Switching is the repeated action; typing /mcpctl every time is friction.
+    expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain("slashName: 'mcpctl'");
+    expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain("key: '<leader>m'");
+  });
+
+  it('tear the outgoing mount down before re-pointing it', () => {
+    // An abandoned client keeps its mcp-session-id — and a gated project's
+    // unlocked state — alive on mcplocal.
+    expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain('mcp.disconnect({ name: SERVER_NAME })');
+  });
+
+  it('clip rather than wrap the footer label on the narrow home prompt', () => {
+    expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain('wrapMode="none"');
+  });
+
   it('switch without rewriting the plugin file opencode has already loaded', () => {
     expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain("'--skip-plugin'");
     expect(OPENCODE_TUI_PLUGIN_SOURCE).toContain("'--skip-marker'");