v0.4.0: turnkey Databricks installer + workflow-coverage spec

Bump .claude-plugin/plugin.json version to 0.4.0. Notable changes since
v0.3.4:

- scripts/genie-install: single-file Python installer for Databricks
  Genie Code. Notebook-native (no env vars, no CLI required). Defaults
  to user-scoped install; --shared for workspace-wide; --main for
  development against main branch.

- .github/workflows/release-genie-bundle.yml: auto-publish the bundle
  + installer as release assets on every tag.

- skills/helix/SKILL.md: §Catalog Resolution gains a full inline
  artifact-type index (44 types × 7 activities) so common queries
  answer without filesystem traversal. §Operating Discipline gains
  four refusal rules from TP-014-A §5 (short affirmations, scope
  complaints, operator pushback, check-mode improvising design).

- FEAT-014: workflow-coverage feature spec covering 13 scenarios
  across 5 runtimes.

- TP-014 + TP-014-A: workflow test plan + real-world pattern
  appendix from 297 user prompts in Claude + Codex session logs.

- .claude-plugin/marketplace.json: marketplace listing for Claude
  Code marketplace install (schema-validated).

Known open: bead helix-96f7dd34 (Genie catalog reachability beyond
the inline index) still unmeasured against the v0.4.0 SKILL.md.

Author: easel

.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "helix",
-  "version": "0.3.4",
+  "version": "0.4.0",
   "description": "HELIX methodology, artifact catalog, and routing skill for AI-assisted development.",
   "author": {
     "name": "Erik LaBianca",