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/fixtures/compact-content-benchmark-baseline.json

@@ -8,39 +8,39 @@
   "label": "PROXY-TOKENIZER DELTA — gpt-tokenizer is a stand-in; Anthropic publishes no tokenizer for Claude 3+. The on/off COMPARISON is exact under this pinned tokenizer; absolute counts are not Claude's real token counts.",
   "splits": {
     "complete-milestone": {
-      "offTokens": 13297,
-      "onTokens": 8408,
-      "reductionPct": 36.77
+      "offTokens": 12833,
+      "onTokens": 8176,
+      "reductionPct": 36.29
     },
     "docs-update": {
-      "offTokens": 14271,
-      "onTokens": 11922,
-      "reductionPct": 16.46
+      "offTokens": 14036,
+      "onTokens": 11687,
+      "reductionPct": 16.74
     },
     "execute-phase": {
-      "offTokens": 25390,
-      "onTokens": 23052,
-      "reductionPct": 9.21
+      "offTokens": 24960,
+      "onTokens": 22854,
+      "reductionPct": 8.44
     },
     "new-project": {
-      "offTokens": 14337,
-      "onTokens": 12398,
-      "reductionPct": 13.52
+      "offTokens": 14038,
+      "onTokens": 12099,
+      "reductionPct": 13.81
     },
     "plan-phase": {
-      "offTokens": 28551,
-      "onTokens": 25213,
-      "reductionPct": 11.69
+      "offTokens": 28087,
+      "onTokens": 24981,
+      "reductionPct": 11.06
     },
     "verify-work": {
-      "offTokens": 13424,
-      "onTokens": 11455,
-      "reductionPct": 14.67
+      "offTokens": 13192,
+      "onTokens": 11223,
+      "reductionPct": 14.93
     }
   },
   "aggregate": {
-    "offTokens": 109270,
-    "onTokens": 92448,
-    "reductionPct": 15.39
+    "offTokens": 107146,
+    "onTokens": 91020,
+    "reductionPct": 15.05
   }
 }