feat: complete code cleanup and create feature parity plan

Major Architecture Improvements:
- Separate JavaScript library (lib/) with proper build system
- Go CLI with embedded library using go:embed
- Hot reload development with Air integration
- Library + CLI build pipeline with npm run build

Code Cleanup:
- Remove obsolete assets (insertr-cli/assets/editor/)
- Clean up package.json metadata and dependencies
- Update .gitignore for new architecture
- Remove unused 'marked' dependency

New Documentation:
- Add comprehensive TODO.md with feature gap analysis
- Document critical gaps between prototype and current library
- Create phased implementation plan for feature parity
- Update DEVELOPMENT.md with hot reload workflow
- Add LIBRARY.md documenting new architecture

Hot Reload System:
- Air watches both Go CLI and JavaScript library
- Library changes trigger: rebuild → copy → CLI rebuild → serve
- Seamless development experience across full stack

Next Steps:
- Current library is basic proof-of-concept (prompt() editing)
- Archived prototype has production-ready features
- Phase 1 focuses on professional forms and authentication
- Phase 2 adds validation and content persistence

package-lock.json

@@ -8,9 +8,6 @@
       "name": "insertr",
       "version": "0.1.0",
       "license": "MIT",
-      "dependencies": {
-        "marked": "^16.2.1"
-      },
       "devDependencies": {
         "live-server": "^1.2.2"
       },
@@ -1147,18 +1144,6 @@
         "node": ">=0.10.0"
       }
     },
-    "node_modules/marked": {
-      "version": "16.2.1",
-      "resolved": "https://registry.npmjs.org/marked/-/marked-16.2.1.tgz",
-      "integrity": "sha512-r3UrXED9lMlHF97jJByry90cwrZBBvZmjG1L68oYfuPMW+uDTnuMbyJDymCWwbTE+f+3LhpNDKfpR3a3saFyjA==",
-      "license": "MIT",
-      "bin": {
-        "marked": "bin/marked.js"
-      },
-      "engines": {
-        "node": ">= 20"
-      }
-    },
     "node_modules/micromatch": {
       "version": "3.1.10",
       "resolved": "https://registry.npmjs.org/micromatch/-/micromatch-3.1.10.tgz",