feat: POSIX/P2P roadmap — proc surfaces, syscalls, boot perf, docs, CI

- Align posix-conformance-matrix bareOsSyscallOps with getconf BARE_OS_SYSCALL_OPS
- Add verify-boot-policy-extension-signer-pins.mjs to pretest; document in scripts/README
- Document extensionSignerPinsV2–V5 env wiring in OTA_AND_BUNDLES; vault multisig sketch
- Note telemetry NDJSON redaction limits in environment appendix
- Expand booter CHANGELOG 1.40.0 (boot-perf, shell POSIX mode, subprocess errors, etc.)
- Holepunch sync README: NDJSON summary path

Seeder/kernel parity and pretest already green for bundled changes.

developer-guide/02-the-context-object.md

@@ -191,6 +191,29 @@ async function run(ctx, argv) {
 }
 ```
 
+**Selective `/lib/bare` warm-cache drop after manifest edits**
+
+When an operator writes a new `bare-module-manifest.json` payload (same bytes as would be stored on the system drive), evict only the bundled `ctxKey` rows instead of flushing all of `/bin` + `/lib/bare`:
+
+```js
+async function run(ctx, argv) {
+  const manifestBuf = await ctx.vfs.readFile('/lib/bare/bare-module-manifest.json')
+  if (manifestBuf && typeof ctx.bareOsInvalidateWarmReadCachesFromBareManifestJson === 'function') {
+    ctx.bareOsInvalidateWarmReadCachesFromBareManifestJson(manifestBuf)
+  }
+}
+```
+
+**Read the Protomux extension registry mirror** (when `BARE_OS_PROC_PROTOMUX_EXTENSIONS_REGISTRY` is enabled on the booter):
+
+```js
+async function run(ctx) {
+  if (typeof ctx.bareOsReadProtomuxExtensionsJson !== 'function') return
+  const reg = ctx.bareOsReadProtomuxExtensionsJson()
+  ctx.console.log(JSON.stringify(reg, null, 2))
+}
+```
+
 ---
 
 ## See also