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/modules/expected/0717-modules-cli-parse.stdout

@@ -0,0 +1,50 @@
+dispatch-group: ok
+dispatch-command: ok
+dispatch-index: ok
+flag-value: ok
+flag-value-set: ok
+bool-set: ok
+json-set: ok
+no-rest: ok
+value-is-view: ok
+group-is-view: ok
+dispatch-2nd: ok
+2nd-bool: ok
+2nd-json-unset: ok
+sep-value: ok
+sep-rest-len: ok
+sep-rest-0: ok
+sep-rest-1: ok
+sep-no-bool: ok
+bare-rest-len: ok
+bare-rest-0: ok
+dash-value: ok
+err-zero-args: ok
+err-unknown-cmd: ok
+err-unknown-group: ok
+err-too-few: ok
+err-unknown-flag: ok
+err-missing-value: ok
+err-value-eats-flag: ok
+err-missing-req: ok
+err-too-many-flags: ok
+diag-flag-tag: ok
+diag-flag-token: ok
+diag-cmd-tag: ok
+diag-cmd-token: ok
+diag-group-tag: ok
+diag-group-token: ok
+diag-too-few-tag: ok
+diag-too-few-token: ok
+diag-zero-args-tag: ok
+diag-zero-args-token: ok
+diag-missing-value-tag: ok
+diag-missing-value-token: ok
+diag-value-eats-tag: ok
+diag-value-eats-token: ok
+diag-req-tag: ok
+diag-req-token: ok
+diag-req-index: ok
+diag-too-many-tag: ok
+diag-too-many-token: ok
+=== DONE ===