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/settings-integrations.test.cjs

@@ -193,7 +193,7 @@ describe('#3651 workflow — review.models settable-set rule', () => {
   test("workflow enumerates exactly the registry's settable review.models lanes (#3651)", () => {
     const registryKeys = collectReviewerModelConfigKeys();
     assert.ok(
-      registryKeys.size >= 9,
+      registryKeys.size >= 8,
       `expected the shipped model-bearing lane set from the registry, found ${registryKeys.size}`
     );
     const src = fs.readFileSync(WORKFLOW_PATH, 'utf-8');