refactor(coding-agent): flattened directory structure, eliminated core/ folder

- Eliminated core/ directory (252 files, 23 subdirs → distributed)
- Reduced max nesting from 9 levels to 5 levels
- Promoted tool subdirs to top level: exa/, lsp/, patch/, task/, web/
- Merged web-scrapers/ + web-search/ into web/{scrapers,search}/
- Flattened modes/interactive/ to modes/
- Split execution/ into: ipy/ (python), exec/ (bash), ssh/
- Renamed ipy/python-*.ts to ipy/*.ts (executor, kernel, etc.)
- Flattened cursor/exec-bridge.ts to cursor.ts
- Created logical groupings: config/, session/, extensibility/, export/
- Updated all imports across 500+ files

packages/coding-agent/src/cli/update-cli.ts

@@ -12,7 +12,7 @@ import { Readable } from "node:stream";
 import { pipeline } from "node:stream/promises";
 import chalk from "chalk";
 import { APP_NAME, VERSION } from "$c/config";
-import { theme } from "$c/modes/interactive/theme/theme";
+import { theme } from "$c/modes/theme/theme";
 
 /**
  * Detect if we're running as a Bun compiled binary.