test: group examples into per-category folders

Move examples/*.sx and their expected/ snapshots into per-category
subfolders (examples/<category>/...). Folder = leading filename token,
with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus
runner and LSP sweep now discover each category's expected/ dir, while
issues/ stays flat. Example 1058's repo-root-relative companion import
is made file-relative. Path strings embedded in 164 snapshots were
regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.

examples/generics/0209-generics-value-param-integral-float.sx

@@ -0,0 +1,19 @@
+// A generic value parameter (`$K: u32`) binds a literal (`Vec(3, i64)`) and an
+// integral-float named const (`Vec(L, i64)` with `L : f64 : 4.0`) to the same
+// integer a plain `4` would — the value-param arg folds through the shared
+// const-int evaluator, so the integral-float rule (F0.4 attempt 8, Agra ruling)
+// reaches value params too. The folded value is the array length `[K]i64`.
+//
+// The bind is range-checked against the declared `u32` (an out-of-range arg is a
+// clean compile error — see 1134); a valid in-range value binds normally.
+#import "modules/std.sx";
+
+Vec :: struct ($K: u32, $T: Type) { data: [K]T; }
+
+L : f64 : 4.0;
+
+main :: () {
+    a : Vec(3, i64) = ---;       // literal value param
+    b : Vec(L, i64) = ---;       // integral-float named-const value param → 4
+    print("a.len={} b.len={}\n", a.data.len, b.data.len);   // 3 and 4
+}