v0.6.1 — single-source analyzer rules

Analyzer design rules are now single-sourced: each rule is authored once and
rendered into both the prompt's full guidance and its one-line self-check, so
the two can no longer drift apart. No change to the design judgment itself —
eval holds at 6/6 on vanilla petclinic with no regression versus v0.6.0.

Changed

• Rule-as-object model in the analyzer prompt. analyzer.md defines a Rule
  concept (id / title / guidance / why / appliesWhen / severity /
  assertion); the rules/*.md files carry normalized frontmatter plus an
  assertion: line, and the prompt gains an explicit "Apply the rules" step.
• AnalyzeService loads rules once and renders them twice. Rules are read
  into a single Rule record and rendered into both {RULES} (full guidance)
  and {SELF_CHECK_RULES} (one assertion line each) from the same objects;
  the separate dev/jar loaders collapse into one loadRules().