refactor(build): remove sidecar models-snapshot distribution

The models snapshot is now embedded directly in the compiled binary,
eliminating the need for a separate models-snapshot.json file alongside
the CLI executable.

- Delete script/kilocode/models-snapshot.ts build-time preparation
- Delete src/kilocode/provider/models-snapshot.ts runtime loader
- Remove snapshot copy steps from vscode, jetbrains, and opencode builds
- Remove snapshot existence checks from PrepareLocalCliTask/CheckCliTask
- Remove snapshot-related .gitignore and .prettierignore entries
- Simplify watch-cli, local-bin, and build scripts
- Update smoke test error messages to say "embedded" not "sidecar"
- Simplify models-snapshot tests to validate parsing only
- Remove models-snapshot from extract-source-links skip list

.github/workflows/publish.yml

@@ -288,7 +288,7 @@ jobs:
             $output = & $binary --pure models anthropic
             if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
             if (-not ($output -match "(?m)^anthropic/")) {
-              throw "Compiled Windows binary did not list Anthropic models from the sidecar snapshot"
+              throw "Compiled Windows binary did not list Anthropic models from the embedded snapshot"
             }
           } finally {
             Remove-Item -Recurse -Force $root -ErrorAction SilentlyContinue