Add oxlint import/no-cycle and break existing src/common cycles

Enable oxlint's import/no-cycle rule (import plugin) so circular module
dependencies are caught in CI, similar to eslint-plugin-import/no-cycle
and biome no-import-cycles discussed in the issue.

Relocate shared types and dependencies to remove cycles under src/common:

- Types.ts: host IInsertEvent, IDeleteEvent, IParams, UnderlineStyle,
  IBuffer, and IBufferSet; drop imports from CircularList, buffer/Types,
  parser/Types, and Services
- CoreTerminal.ts: define and export ICoreTerminal
- ServiceRegistry.ts: define IServiceIdentifier (break Services registry loop)
- UnicodeService: stop constructing UnicodeV6; CoreTerminal registers the
  default v6 provider after service creation
- buffer/Types.ts and parser/Types.ts: re-export moved types for callers

Fixes https://github.com/xtermjs/xterm.js/issues/5897

Co-authored-by: Cursor <cursoragent@cursor.com>

src/common/input/UnicodeV6.ts

@@ -132,6 +132,7 @@ export class UnicodeV6 implements IUnicodeVersionProvider {
   public charProperties(codepoint: number, preceding: UnicodeCharProperties): UnicodeCharProperties {
     let width = this.wcwidth(codepoint);
     let shouldJoin = width === 0 && preceding !== 0;
+    // HACK: Ideally this file would not depend on the service which uses it
     if (shouldJoin) {
       const oldWidth = UnicodeService.extractWidth(preceding);
       if (oldWidth === 0) {