refactor(tools): bin/{subject}/{method} layout; Go serve+watch modules

Move serve/ (module) -> bin/server, tools/ -> bin/tools, replace bin/kb-watch
bash with bin/watch Go package; self-executing Go shebangs bin/serve.go and
bin/kb/watch.go; Docker + CI + git/import + docs repointed. Multi-stage image
builds static serve+watch binaries (no Go runtime in container).

bin/tools/yamlout.py

@@ -0,0 +1,48 @@
+"""Minimal YAML emitter.
+
+Agents read YAML more cheaply than JSON and the output stays diffable. This is
+deliberately tiny: it emits the shapes these tools produce, nothing more.
+"""
+from __future__ import annotations
+
+import json
+
+
+def to_yaml(node, indent: int = 0) -> str:
+    pad = "  " * indent
+    if isinstance(node, dict):
+        if not node:
+            return f"{pad}{{}}\n"
+        out = ""
+        for key, value in node.items():
+            if isinstance(value, (dict, list)) and value:
+                out += f"{pad}{key}:\n{to_yaml(value, indent + 1)}"
+            elif isinstance(value, (dict, list)):
+                out += f"{pad}{key}: {'{}' if isinstance(value, dict) else '[]'}\n"
+            else:
+                out += f"{pad}{key}: {scalar(value)}\n"
+        return out
+    if isinstance(node, list):
+        out = ""
+        for item in node:
+            if isinstance(item, dict):
+                out += f"{pad}-\n{to_yaml(item, indent + 1)}"
+            else:
+                out += f"{pad}- {scalar(item)}\n"
+        return out
+    return f"{pad}{scalar(node)}\n"
+
+
+def scalar(value) -> str:
+    if value is None:
+        return "null"
+    if isinstance(value, bool):
+        return "true" if value else "false"
+    if isinstance(value, (int, float)):
+        return str(value)
+    text = str(value)
+    if "\n" in text:
+        return json.dumps(text, ensure_ascii=False)
+    if text == "" or any(ch in text for ch in ":#'\"[]{}&*!|>%@`") or text != text.strip():
+        return json.dumps(text, ensure_ascii=False)
+    return text