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/opencode-command-dir-plural.test.cjs

@@ -434,33 +434,3 @@ describe('#2329: upgrading an install with an orphaned command/ dir migrates it
     }
   });
 });
-
-// ---------------------------------------------------------------------------
-// 6. No collateral: another flat-command-dir runtime (Kilo) is unaffected.
-// ---------------------------------------------------------------------------
-//
-// NOTE: this test is expected to PASS both before and after the #2329 fix —
-// it is a regression guard against the fix accidentally widening scope to
-// Kilo (which also uses a flat, singular `command/` dir per its own
-// capability.json and is NOT part of this issue), not a red-phase test for
-// the bug itself.
-
-describe('#2329: the fix must not affect other runtimes\' command output directories', () => {
-  test('kilo global install still writes to command/ (singular) — unaffected by the opencode-only fix', (t) => {
-    const { configDir, root } = runMinimalInstall({ runtime: 'kilo', scope: 'global' });
-    t.after(() => cleanup(root));
-
-    const singularDir = path.join(configDir, 'command');
-    const pluralDir = path.join(configDir, 'commands');
-
-    assert.ok(
-      msdMdFiles(singularDir).length >= 60,
-      `kilo must still write its command files to the singular command/ dir, got ` +
-      `${msdMdFiles(singularDir).length} files under ${singularDir}`
-    );
-    assert.ok(
-      !fs.existsSync(pluralDir),
-      `kilo must NOT gain a commands/ (plural) dir as collateral from the opencode-only #2329 fix`
-    );
-  });
-});