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/err-write-try-catch-first.md

@@ -0,0 +1,53 @@
+---
+title: Write Try-Catch-Finally First
+impact: HIGH
+impactDescription: prevents missing error handling cases
+tags: err, try-catch, tdd, boundaries
+---
+
+## Write Try-Catch-Finally First
+
+When writing code that could throw exceptions, start with the try-catch-finally statement. This helps define what the user of the code should expect, regardless of what goes wrong in the try block.
+
+**Incorrect (error handling added as afterthought):**
+
+```java
+// Written without considering error cases
+public List<RecordedGrip> retrieveSection(String sectionName) {
+    FileInputStream stream = new FileInputStream(sectionName);
+    BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
+    String line;
+    List<RecordedGrip> grips = new ArrayList<>();
+    while ((line = reader.readLine()) != null) {
+        grips.add(parseGrip(line));
+    }
+    return grips;
+    // What if file doesn't exist? What if parsing fails?
+}
+```
+
+**Correct (start with try-catch structure):**
+
+```java
+// TDD approach: start with test for exception case
+@Test(expected = StorageException.class)
+public void retrieveSectionShouldThrowOnInvalidFileName() {
+    sectionStore.retrieveSection("invalid-file");
+}
+
+// Then write code starting with try-catch
+public List<RecordedGrip> retrieveSection(String sectionName) throws StorageException {
+    try (var stream = new FileInputStream(sectionName)) {
+        return readGrips(stream);
+    } catch (IOException e) {
+        throw new StorageException("Error reading section: " + sectionName, e);
+    }
+}
+```
+
+**Benefits:**
+- Forces you to consider error cases first
+- Establishes clear transaction boundaries
+- The finally block ensures cleanup happens
+
+Reference: [Clean Code, Chapter 7: Error Handling](https://www.oreilly.com/library/view/clean-code-a/9780136083238/)