refactor: drop 12 runtimes, keep Claude, Codex, OpenCode, Cursor, ZCode, Antigravity

Removes kilo, kimi, kimi-code, copilot, windsurf, augment, trae, qwen, hermes,
cline, codebuddy and pi end to end: capability descriptors, installer branches
and converters (bin/install.js 14.9k -> 11.2k lines), TypeScript converters,
hook surfaces and runtime homes, review lanes qwen/kimi-code, the two pi
migrations, Kimi payload normalization in the hook guards, dead hostBehaviors
vocabulary, launcher home probes, fixtures, runtime-specific tests and the
prose that presented them as supported.

Installer output for the six kept runtimes is byte-identical to before the
prune. The Kimi tool-vocabulary tests in workflow-guard, read-guard and
read-injection-scanner are left in place pending a decision.

tests/execute-phase-active-flags.test.cjs

@@ -537,13 +537,9 @@ describe('#3177: execute-phase.md states Claude Code dispatch truthfully', () =>
     }
   });
 
-  test('the Copilot and multi-plan dispatch rules survive the correction', () => {
+  test('the multi-plan dispatch rules survive the correction', () => {
     // Row 6 — negative space. These were already true and are adjacent to the edit.
     const text = workflowText();
-    assert.ok(
-      text.includes('- **Copilot:** Subagent spawning does not reliably return completion signals.'),
-      'the Copilot bullet must survive verbatim',
-    );
     assert.ok(
       text.includes('one at a time with `run_in_background: true`'),
       'the multi-plan wave prescription must survive verbatim',