Silence render-disposed spam, unbreak bundled skills, drop board wake

Three independently ugly bugs that all fed the same log flood:

* Electron's `WebFrameMain.send` writes every "Render frame was disposed"
  to stderr via `console.error`. When the worker fans a second
  agent-event past a reloading renderer, we produced thousands of
  identical lines and stalled the main loop on stderr I/O. Added a
  `mainFrame.detached` guard so the send is short-circuited before
  Electron's own catch block fires, and installed a targeted filter in
  `suppress-warnings.ts` (now actually imported from the entry point)
  so the specific `console.error("Error sending from webFrameMain:"…)`
  noise never reaches the terminal. Any other payload still surfaces.

* `dispatchAgentMessage` accepted the human-reader sentinel as a wake
  target when an agent replied to `__board__` — `wakeAgentIfPossible`
  then called `db.getAgent("__board__")`, threw, and the dispatcher
  kept repeating on every send. Strip `HUMAN_SENDER_ID` at
  `resolveMessageWakeTargets`, and keep a defense-in-depth guard in the
  heartbeat so a stray caller (future automation fan-out) cannot
  reintroduce the crash.

* Pi's skills loader rejects any SKILL.md whose frontmatter `name`
  diverges from its parent directory. The four bundled `my-writing-style`
  copies declared `name: writing-style-skill`, so every install emitted
  a warning and dropped the skill. They also lived as orphan gitlinks
  (mode 160000 without .gitmodules), and the global `*.md` gitignore
  hid every other SKILL.md from version control. Fixed the frontmatter
  to match the dir, converted the dangling submodules to plain trees,
  and allowlisted `builtin-skills/**/*.md` so a fresh clone carries the
  catalogue instead of silently losing it.

builtin-skills/software-engineer/clean-code/references/cmt-avoid-redundant.md

@@ -0,0 +1,68 @@
+---
+title: Avoid Redundant Comments
+impact: HIGH
+impactDescription: eliminates noise that obscures important information
+tags: cmt, redundant, noise, clutter
+---
+
+## Avoid Redundant Comments
+
+A comment that merely restates what the code does is worse than no comment. It adds clutter, becomes stale, and trains readers to ignore comments entirely.
+
+**Incorrect (redundant comments):**
+
+```java
+/**
+ * The name of the customer
+ */
+private String customerName;
+
+/**
+ * Returns the name
+ * @return the name
+ */
+public String getName() {
+    return name;
+}
+
+// Check if the account is closed
+if (account.isClosed()) {
+    // Throw an exception
+    throw new AccountClosedException();
+}
+
+/**
+ * Default constructor
+ */
+public Account() {
+}
+```
+
+**Correct (comment only when necessary):**
+
+```java
+private String customerName;
+
+public String getName() {
+    return name;
+}
+
+if (account.isClosed()) {
+    throw new AccountClosedException();
+}
+
+public Account() {
+}
+
+// Comments that add value:
+
+// RFC 2822 date format required by legacy email parser
+private static final String DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss Z";
+
+// Thread-safe: ConcurrentHashMap handles synchronization
+private Map<String, Session> activeSessions = new ConcurrentHashMap<>();
+```
+
+**Rule of thumb:** If the comment just repeats the code in English, delete it.
+
+Reference: [Clean Code, Chapter 4: Comments](https://www.oreilly.com/library/view/clean-code-a/9780136083238/)