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-express-in-code.md

@@ -0,0 +1,58 @@
+---
+title: Express Yourself in Code, Not Comments
+impact: CRITICAL
+impactDescription: eliminates stale comment risk
+tags: cmt, self-documenting, refactoring, clarity
+---
+
+## Express Yourself in Code, Not Comments
+
+In many cases, creating a function that says the same thing as the comment you wanted to write is better. Code can be refactored to be self-explanatory.
+
+**Incorrect (comment explains obscure code):**
+
+```java
+// Check to see if the employee is eligible for full benefits
+if ((employee.flags & HOURLY_FLAG) && (employee.age > 65)) {
+    // ...
+}
+
+// Add 30 days to the current date
+Date newDate = new Date(currentDate.getTime() + (30L * 24 * 60 * 60 * 1000));
+
+// Returns true if the string contains only digits
+boolean result = str.matches("[0-9]+");
+```
+
+**Correct (code expresses intent):**
+
+```java
+if (employee.isEligibleForFullBenefits()) {
+    // ...
+}
+
+// In Employee class:
+public boolean isEligibleForFullBenefits() {
+    return isHourlyWorker() && age > RETIREMENT_AGE;
+}
+
+Date newDate = currentDate.plusDays(30);
+
+boolean result = StringUtils.isNumeric(str);
+// Or define your own:
+boolean result = containsOnlyDigits(str);
+```
+
+**Benefits:**
+- Function names are searchable
+- Functions can be tested
+- Code documents itself
+- No risk of comment becoming stale
+
+**When comments are still valuable:**
+- **Why, not what:** Comments explaining *why* a decision was made (business rules, regulatory requirements, algorithm choices) cannot be replaced by code.
+- **Warnings:** Thread-safety, performance implications, or non-obvious side effects deserve explicit comments.
+- **Legal/license comments:** Required by policy and cannot be expressed as code.
+- **Public API documentation:** Javadoc/docstrings for public APIs are expected and useful.
+
+Reference: [Clean Code, Chapter 4: Comments](https://www.oreilly.com/library/view/clean-code-a/9780136083238/)