fix: resolve functionsDir relative to ruleset file, not process CWD. …

[jeremnaf]

…Closes #44

Related Issue

Closes #44

---

What does this PR do?

When a ruleset declares functionsDir: ./functions (a path relative to the ruleset file), Polychro was resolving it against the process working directory (CWD) instead of the ruleset file's parent directory. This caused custom JS functions to be silently skipped whenever --ruleset was passed as an absolute (or otherwise non-CWD-relative) path.

Root cause: RulesetValidatorFactory.create() correctly computed baseDir from the ruleset path, but never passed it to new RulesetValidator(ruleset, includeNonRecommended). Inside that constructor, Path.of(ruleset.functionsDir()) created a CWD-relative path that could not be resolved to the actual scripts.

Fix:

• Add RulesetValidator(Ruleset, Path baseDir, boolean) constructor that resolves functionsDir against baseDir via baseDir.resolve(raw).normalize() when baseDir is non-null.
• Keep the existing two-arg constructor as a delegate (baseDir = null) to preserve the current CWD-relative behaviour for inline-content rulesets.
• RulesetValidatorFactory.create() now extracts baseDir from rulesetPath and forwards it to the new three-arg constructor; the content-only path continues to use the two-arg constructor.

---

Tests

Added FunctionsDirResolutionTest in polychro-ruleset-polyglot:

• Writes a ruleset with functionsDir: ./functions to a JUnit @TempDir alongside a copy of unique-namespaces.js.
• Loads the ruleset via its absolute path while the process CWD is a different directory (the @TempDir root, not the rules/ sub-directory).
• Asserts that the custom JS function fires and produces a naftiko-unique-namespaces diagnostic.

This test was written first (RED), then the fix was applied (GREEN), confirming the regression. All 637 existing tests in polychro-api, polychro-ruleset, and polychro-ruleset-polyglot continue to pass.

---

Checklist

• CI is green (build + tests)
• Rebased on latest main
• Small and focused — one concern per PR
• Commit messages follow Conventional Commits
• Apache 2.0 license header present on any new Java file

---

Agent Context (optional)

agent_name: GitHub Copilot
llm: Naftiko Claude Sonnet 4.6
tool: VS Code
confidence: high
source_event: issue #44
discovery_method: user_report
files_suspected:
  - polychro-ruleset/src/main/java/io/polychro/ruleset/RulesetValidatorFactory.java
  - polychro-ruleset/src/main/java/io/polychro/ruleset/RulesetValidator.java

[eskenazit]

Good fix overall — the core logic in RulesetValidator and RulesetValidatorFactory is correct and well-tested. One observation on the regression test (1).

[eskenazit]

LGTM