chore: rename markitect_project to markitect-main across project

Finishes the in-progress rename so docs, configs, tests, and capability
manifests all reference the current repo name consistently. Fixes two
tests (test_roundtrip_consolidated.py, test_issue_140_roundtrip_simplified.py)
whose hardcoded cwd paths would have broken under the renamed directory.

Archival content under history/, reports/, and roadmap/eat-the-frog/, plus
derived artifacts (.venv_old/, node_modules/, asset_registry.json) are
intentionally left untouched.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package-lock.json

@@ -1,11 +1,11 @@
 {
-  "name": "markitect_project",
+  "name": "markitect-main",
   "version": "1.0.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
-      "name": "markitect_project",
+      "name": "markitect-main",
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {