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/runtime-artifact-install-plan.test.cjs

@@ -34,7 +34,6 @@ describe('createRuntimeArtifactInstallPlan', () => {
         kind('commands', 'commands', '/tmp/staged-commands', calls),
         kind('agents', 'agents', '/tmp/staged-agents', calls),
         kind('skills', 'skills', '/tmp/staged-skills', calls),
-        kind('kimi-agents', 'agents', '/tmp/staged-kimi-agents', calls),
       ],
     };
 
@@ -57,12 +56,10 @@ describe('createRuntimeArtifactInstallPlan', () => {
       ['commands', 'core'],
       ['agents', 'core'],
       ['skills', 'core'],
-      ['kimi-agents', 'core'],
     ]);
     assert.deepStrictEqual(rewriteCalls, [
       ['commands', '/tmp/staged-commands', 'claude', configDir, 'global'],
       ['skills', '/tmp/staged-skills', 'claude', configDir, 'global'],
-      ['skills', '/tmp/staged-kimi-agents', 'claude', configDir, 'global'],
     ]);
     assert.deepStrictEqual(result, {
       ok: true,
@@ -72,7 +69,6 @@ describe('createRuntimeArtifactInstallPlan', () => {
           { kind: 'commands', sourceDir: '/tmp/staged-commands-rewritten', destDir: path.join(configDir, 'commands') },
           { kind: 'agents', sourceDir: '/tmp/staged-agents', destDir: path.join(configDir, 'agents') },
           { kind: 'skills', sourceDir: '/tmp/staged-skills', destDir: path.join(configDir, 'skills') },
-          { kind: 'kimi-agents', sourceDir: '/tmp/staged-kimi-agents', destDir: path.join(configDir, 'agents') },
         ],
       },
     });