Use rolling Fable and Opus model aliases

[ericlitman]

Context

Fable 5.1 is available, but Open Pstack currently pins Claude lanes and generated model sheets to Fable 5 and Opus 5 model IDs. Claude Code supports the rolling fable and opus aliases, which resolve to the latest revision.

Scope

• Replace active Fable and Opus model identifiers with fable and opus across provider dispatch, native Claude agents, role defaults, runner coverage, static checks, and current documentation.
• Keep historical upstream and changelog records intact where they describe an earlier release.
• Make /setup-pstack recognize previously generated versioned Claude Fable and Opus descriptors, normalize them to the rolling aliases before matrix validation, preserve role assignments and requested efforts, and rewrite the normalized sheet plus Codex mirror only after the existing probe and confirmation gates pass.
• Add a durable invariant that prevents active version-pinned Fable or Opus identifiers from returning.
• Release the change as the next patch version.

Acceptance criteria

• New installs and first-run setup use claude:fable@<effort> and claude:opus@<effort>.
• Existing setup sheets with versioned Fable or Opus descriptors migrate without changing role families, lane order, or effort selections.
• Claude-native agents and external Claude runner calls pass fable or opus to Claude Code.
• Bun tests, strict typecheck, static invariants, and plugin validation pass.
• The exact release candidate passes live tests from the installed Claude Code and Codex user surfaces.
• The merged commit is tagged and published as a GitHub release.

[ericlitman]

Released and rolled out in Open Pstack 1.2.1 from merged PR #39 (f466256cc684f7cd44ee7e8eaeea2e3904921d84).

Final evidence:

• GitHub CI passed on the PR head and merged main commit; complete suite: 158 tests, 657 assertions.
• Installed Claude-native fable resolved to claude-fable-5-1; opus resolved to claude-opus-5.
• Installed Codex external-runner receipts verified the same concrete families from provider reports.
• Runtime dispatch normalizes legacy sheets before route selection; /setup-pstack persists the migration after its existing gates; the runner rejects any missed version pin.
• studio2 and pro14 now have enabled user-scope 1.2.1 installations in both ~/.claude and ~/.codex, sourced from GitHub/tag v1.2.1; all four payloads match the release and only cache version 1.2.1 remains.
• pro14's existing Codex sheet and bounded AGENTS mirror were migrated in place: 8 Fable and 5 Opus descriptors now use rolling aliases, with byte-identical sheet/mirror content.
• Announcement thread: https://x.com/ericlitman/status/2094888570292928661