restore: recover deleted documentation, CI/CD, and infrastructure files

Restored from origin/main (b4663fb):
- .github/ workflows and issue templates
- .gitignore (proper exclusions)
- .opencode/agent/web_developer.md
- AGENTS.md, BUILD.md, PROGRESS.md
- dev-docs/ (9 architecture/implementation docs)
- docs/screenshots/ (4 UI screenshots)
- images/ (CodeNomad icons)
- package-lock.json (dependency lockfile)
- tasks/ (25+ project task files)

Also restored original source files that were modified:
- packages/ui/src/App.tsx
- packages/ui/src/lib/logger.ts
- packages/ui/src/stores/instances.ts
- packages/server/src/server/routes/workspaces.ts
- packages/server/src/workspaces/manager.ts
- packages/server/src/workspaces/runtime.ts
- packages/server/package.json

Kept new additions:
- Install-*.bat/.sh (enhanced installers)
- Launch-*.bat/.sh (new launchers)
- README.md (SEO optimized with GLM 4.7)

tasks/done/021-file-attachments.md

@@ -0,0 +1,40 @@
+---
+title: File Attachments
+description: Add @mentions, drag & drop, and chips for files.
+---
+
+Implement File Attachments
+
+---
+
+### Implement @ Mentions
+
+When a user types `@` in the input field, display a file picker with search functionality.
+
+Allow users to select files to attach to their prompt.
+
+---
+
+### Visual Attachment Chips
+
+Display attached files as interactive chips above the input area.
+
+Chips should include a filename and a removable "x" button.
+
+---
+
+### Drag and Drop Files
+
+Enable dragging files from the operating system directly onto the input area.
+
+Automatically create an attachment chip for dropped files.
+
+---
+
+### Acceptance Criteria
+
+- Typing `@` brings up a file selection autocomplete.
+- Files can be selected and appear as chips.
+- Users can drag and drop files onto the input, creating chips.
+- Attached files are included in the prompt submission.
+- Attachment chips can be removed by clicking "x".