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/obj-data-object-asymmetry.md

@@ -0,0 +1,72 @@
+---
+title: Understand Data/Object Anti-Symmetry
+impact: MEDIUM-HIGH
+impactDescription: prevents 2× effort when requirements change
+tags: obj, asymmetry, procedural, polymorphism
+---
+
+## Understand Data/Object Anti-Symmetry
+
+Objects and data structures are opposites. Objects hide data and expose behavior; data structures expose data and have no behavior. Choose based on what kind of changes you anticipate.
+
+**Incorrect (wrong approach for frequent type additions):**
+
+```java
+// Procedural approach - adding Triangle requires modifying EVERY function
+public class Square { public double side; }
+public class Circle { public double radius; }
+
+public class Geometry {
+    public double area(Object shape) {
+        if (shape instanceof Square) {
+            Square s = (Square) shape;
+            return s.side * s.side;
+        } else if (shape instanceof Circle) {
+            Circle c = (Circle) shape;
+            return Math.PI * c.radius * c.radius;
+        }
+        // Must add Triangle case here AND in perimeter() AND in draw()...
+        throw new NoSuchShapeException();
+    }
+}
+```
+
+**Correct (polymorphic approach for frequent type additions):**
+
+```java
+// Object approach - adding Triangle only requires one new class
+public interface Shape {
+    double area();
+}
+
+public class Square implements Shape {
+    private double side;
+
+    public double area() {
+        return side * side;
+    }
+}
+
+public class Circle implements Shape {
+    private double radius;
+
+    public double area() {
+        return Math.PI * radius * radius;
+    }
+}
+
+// Adding Triangle is easy - just add one class
+public class Triangle implements Shape {
+    private double base, height;
+
+    public double area() {
+        return 0.5 * base * height;
+    }
+}
+```
+
+**Choose based on anticipated changes:**
+- Adding new functions often? Use data structures (procedural)
+- Adding new types often? Use objects (polymorphic)
+
+Reference: [Clean Code, Chapter 6: Objects and Data Structures](https://www.oreilly.com/library/view/clean-code-a/9780136083238/)