feat(lsp): method call hierarchy for extend Type / .Method (0.9)

Index methods inside extend/impl blocks and include .Method( call sites
in the call graph so IDEs can navigate receiver methods.

- analyzeFile: track extend/impl brace scope; kind=method + container
- Call hierarchy treats methods as callables; display Type.Method
- smoke_lsp_method_hierarchy (Scale→Len, Main→Scale)

tools/smoke_lsp_method_hierarchy.sh

@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+# Smoke: method call hierarchy — extend Type + .Method() (bux-lsp 0.9)
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+LSP="$ROOT/tools/bux-lsp"
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+if [[ ! -x "$LSP" ]]; then
+  (cd "$ROOT" && make lsp >/dev/null)
+fi
+
+cat > "$TMP/Main.bux" <<'EOF'
+struct Point {
+    x: int;
+    y: int;
+}
+extend Point {
+    func Len(self: Point) -> int {
+        return self.x + self.y;
+    }
+    func Scale(self: Point, n: int) -> int {
+        return self.Len() * n;
+    }
+}
+func Main() -> int {
+    let p: Point = Point { x: 3, y: 4 };
+    return p.Scale(2);
+}
+EOF
+
+rpc() {
+  local body="$1"
+  local len
+  len=$(printf '%s' "$body" | wc -c)
+  printf 'Content-Length: %s\r\n\r\n%s' "$len" "$body"
+}
+
+CONTENT_JSON=$(python3 -c 'import json,sys; print(json.dumps(open(sys.argv[1]).read()))' "$TMP/Main.bux")
+URI="file://$TMP/Main.bux"
+
+# Len is around line 5 (0-based: extend block)
+# Scale around line 8
+# Main line 11
+{
+  rpc '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"capabilities":{},"rootUri":"file://'"$TMP"'"}}'
+  rpc '{"jsonrpc":"2.0","method":"initialized","params":{}}'
+  rpc '{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"'"$URI"'","languageId":"bux","version":1,"text":'"$CONTENT_JSON"'}}}'
+  # prepare on Len method
+  rpc '{"jsonrpc":"2.0","id":2,"method":"textDocument/prepareCallHierarchy","params":{"textDocument":{"uri":"'"$URI"'"},"position":{"line":5,"character":9}}}'
+  # incoming for Len — expect Scale (method call self.Len())
+  rpc '{"jsonrpc":"2.0","id":3,"method":"callHierarchy/incomingCalls","params":{"item":{"name":"Point.Len","kind":6,"data":"Len","uri":"'"$URI"'","range":{"start":{"line":5,"character":0},"end":{"line":5,"character":12}},"selectionRange":{"start":{"line":5,"character":9},"end":{"line":5,"character":12}}}}}'
+  # outgoing for Scale — expect Len
+  rpc '{"jsonrpc":"2.0","id":4,"method":"callHierarchy/outgoingCalls","params":{"item":{"name":"Point.Scale","kind":6,"data":"Scale","uri":"'"$URI"'","range":{"start":{"line":8,"character":0},"end":{"line":8,"character":14}},"selectionRange":{"start":{"line":8,"character":9},"end":{"line":8,"character":14}}}}}'
+  # incoming for Scale — expect Main
+  rpc '{"jsonrpc":"2.0","id":5,"method":"callHierarchy/incomingCalls","params":{"item":{"name":"Point.Scale","kind":6,"data":"Scale","uri":"'"$URI"'","range":{"start":{"line":8,"character":0},"end":{"line":8,"character":14}},"selectionRange":{"start":{"line":8,"character":9},"end":{"line":8,"character":14}}}}}'
+  rpc '{"jsonrpc":"2.0","id":6,"method":"shutdown","params":null}'
+  rpc '{"jsonrpc":"2.0","method":"exit","params":null}'
+} | "$LSP" 2>/dev/null | tr '\r' '\n' > "$TMP/out.txt"
+
+if ! grep -q '0.9.0' "$TMP/out.txt"; then
+  echo "WARN: version not 0.9.0"
+fi
+
+# prepare should return method (Point.Len or Len)
+if ! grep -qE '"name":"(Point\.)?Len"' "$TMP/out.txt"; then
+  echo "FAIL: prepare did not return Len method"
+  cat "$TMP/out.txt"
+  exit 1
+fi
+
+# Scale calls Len
+if ! grep -qE '"name":"(Point\.)?Scale"' "$TMP/out.txt"; then
+  echo "FAIL: missing Scale in hierarchy"
+  cat "$TMP/out.txt"
+  exit 1
+fi
+
+# Main calls Scale
+if ! grep -q '"name":"Main"' "$TMP/out.txt"; then
+  echo "FAIL: incoming Scale should include Main"
+  cat "$TMP/out.txt"
+  exit 1
+fi
+
+# kind 6 = Method somewhere
+if ! grep -q '"kind":6' "$TMP/out.txt"; then
+  echo "FAIL: expected SymbolKind.Method (6)"
+  exit 1
+fi
+
+echo "PASS: LSP method call hierarchy (extend + .Method)"