Merge origin/main (v1.67.2.0) — v1.68.0.0 stays on top

CHANGELOG keeps both entries in release order (1.68.0.0 above 1.67.2.0);
VERSION and package.json keep the branch's higher claim. Generated
SKILL.md files verified byte-exact against a fresh regen from the merged
templates.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/ADDING_A_HOST.md

@@ -60,6 +60,7 @@ That expands to the full `HostConfig` with these defaults:
 
 - `cliCommand: 'myhost'` (the name; binary for `command -v` detection)
 - `cliAliases: []`
+- `defaultModel: 'claude'` (model overlay used when generation gets no explicit `--model`; codex overrides to `'gpt'`)
 - `globalRoot` / `localSkillRoot`: `.myhost/skills/gstack`, `hostSubdir`: `.myhost`
 - `usesEnvVars: true` (false only for Claude, which uses literal `~` paths)
 - `frontmatter`: allowlist keeping `name` + `description`, no description limit
@@ -156,6 +157,7 @@ Key fields:
 
 | Field | Purpose |
 |-------|---------|
+| `defaultModel` | Model overlay rendered when generation gets no explicit `--model` (validated against `ALL_MODEL_NAMES` in `scripts/models.ts`) |
 | `frontmatter.mode` | `allowlist` (keep only listed) or `denylist` (strip listed) |
 | `frontmatter.descriptionLimit` | Max chars, `null` for no limit |
 | `frontmatter.descriptionLimitBehavior` | `error` (fail build), `truncate`, `warn` |
@@ -173,6 +175,7 @@ Key fields:
 The `validateHostConfig()` function in `scripts/host-config.ts` checks:
 - Name: lowercase alphanumeric with hyphens
 - CLI command: alphanumeric with hyphens/underscores
+- `defaultModel`: must be a known model family from `scripts/models.ts` `ALL_MODEL_NAMES`
 - Paths: safe characters only (alphanumeric, `.`, `/`, `$`, `{}`, `~`, `-`, `_`)
 - No duplicate names, hostSubdirs, or globalRoots across configs