fix(extract): compose Spring controller route prefixes

[jonghyunlee-29cm]

What does this PR do?

Distilled from a real Spring/Kotlin route-indexing failure: reindexing still missed actual controller API names because Spring method routes were indexed without their class-level @RequestMapping prefix.

Bug/Background

Spring annotation extraction can already produce method-level routes such as /orders, but push_method_def only inspected the method node. Class-level mappings such as @RequestMapping("/api") or Kotlin's @RequestMapping(value = ["/internal/v1/api"]) were not folded into the method route before Route/HANDLES emission.

That leaves the graph with partial Route node names like /orders instead of the actual endpoint /api/orders, which makes API discovery and route search miss the production route shape even though a HANDLES edge exists.

Fix

• Compose Java/Kotlin class-level Spring mapping prefixes with method-level mapping paths while extracting method definitions.
• Walk bounded annotation-argument subtrees and choose the first path-shaped string literal, covering named and array-valued annotation arguments while ignoring non-route literals such as media types.
• Preserve the existing single-route_path extraction model.

Reproduce-first

• Strengthened the Spring Java edge_types_probe fixture to assert exact Route node names: /api/orders and /api/orders/{id}.
• Strengthened the Spring Kotlin fixture with @RequestMapping(value = ["/internal/v1/api"]) and exact Route node assertions.
• Assert the exact Route node set so stale partial routes such as /orders cannot remain alongside the full route.

Validation

• git diff --check
• GIT_CONFIG_GLOBAL=/dev/null build/c/test-runner edge_types_probe -> 53 passed
• GIT_CONFIG_GLOBAL=/dev/null make -f Makefile.cbm test -> 5747 passed
• GitHub CI lint / lint -> passed (scripts/lint.sh --ci, which provisions cppcheck 2.20.0 and clang-format-20 before running the lint-ci path)

Known limitation

This keeps the existing one-route-per-definition behavior. Multi-path annotations still select the first path-shaped literal rather than expanding into multiple Route nodes.

Checklist

• Every commit is signed off (git commit -s) — required, CI rejects
  unsigned commits (DCO, see CONTRIBUTING.md)
• Tests pass locally (make -f Makefile.cbm test)
• Lint passes (make -f Makefile.cbm lint-ci)
• New behavior is covered by a test (reproduce-first for bug fixes)