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.

docs/INVENTORY-MANIFEST.json

@@ -436,7 +436,6 @@
       "health-diagnostic-types.cjs",
       "health-diagnostic.cjs",
       "hook-bus.cjs",
-      "host-integration-adapters/cline-sdk-binding.cjs",
       "host-integration-adapters/imperative-hook-bus.cjs",
       "host-integration-sdk.cjs",
       "host-integration.cjs",
@@ -460,10 +459,8 @@
       "installer-migrations/003-rename-get-shit-done-to-msd-core.cjs",
       "installer-migrations/004-prune-stale-pristine-snapshots.cjs",
       "installer-migrations/005-opencode-baseline-commands-dir.cjs",
-      "installer-migrations/006-pi-extension-cjs-to-js.cjs",
       "installer-migrations/007-retire-config-root-commonjs-marker.cjs",
       "installer-migrations/008-cursor-retire-commands-surface.cjs",
-      "installer-migrations/009-pi-retire-reserved-hooks-dir.cjs",
       "installer-migrations/010-antigravity-retire-confighome-artifacts.cjs",
       "intel-command-router.cjs",
       "intel.cjs",
@@ -618,8 +615,6 @@
       "msd-statusline.js",
       "msd-update-banner.js",
       "msd-validate-commit.sh",
-      "msd-windsurf-pre-command.js",
-      "msd-windsurf-pre-write.js",
       "msd-workflow-guard.js",
       "msd-worktree-path-guard.js",
       "msd-write-guard.js"