feat(eliminate-frontend-makefile): task 3.3 - update live documentation (11 files)

Removes every live current-fact reference to src/frontend/Makefile
targets or Makefile-specific fixed paths across 11 docs (steering,
frontend/CLAUDE.md, root CLAUDE.md, deployment docs, and two skill
docs), replacing with the Meson-based equivalents established by
tasks 1-3.2: /xce-build apiserver, meson test --suite apiserver,
direct tests/regression/run.sh invocation.

Round-1 review rejected the first pass: xce-deploy-ha/SKILL.md had
over-corrected by deleting all mention of deploy-ha.sh's still-real
/tmp/apiserver legacy fallback (that script's discovery logic is
unchanged, unlike run-resource-verify.sh's, which genuinely lost its
fallback in task 3.1 -- xce-test-resources/SKILL.md's identical-
looking edit was correct for that reason). Fixed by restoring an
accurate, Makefile-free description of the real fallback at all four
touched sites. Re-reviewed and approved.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg

.kiro/steering/structure.md

@@ -95,7 +95,7 @@ Plugin-based components add their own subdirectory:
 **Go tests** (co-located `_test.go`):
 - Table-driven unit tests, `t.TempDir()` for fixtures
 - Global state reset helpers (e.g., `resetRBACState()`) for test isolation
-- `make test` = unit only; `make test-all` = unit + integration
+- `/xce-build apiserver` = unit tests only; add `meson test -C <build_dir> --suite apiserver` (backend) and `tests/regression/run.sh` (integration) for full coverage
 
 ## Code Organization Principles