feat(models): add Claude Haiku 5.5 and use it for Claude text generation

[incognitojam]

Claude Code 2.1.293 ships Claude Haiku 5.5, but styal's Claude model manifest does not list it, so the picker cannot offer it and Claude text generation still defaults to Haiku 4.5.

Upstream added Haiku 5.5 in pingdotgg#16903 (with its context window fixed at 1M by pingdotgg#16908). An early import of that PR does not apply at the fork's reconciled boundary because it conflicts with six earlier pending upstream changes to the manifest, including the new orchestrator, so this adds the entry directly, as #519 did for Sonnet 5.5.

Change

• claude-haiku-5-5 is a current model with a NEW badge, shown only for Claude Code 2.1.293 or newer. Older CLIs see the existing upgrade notice.
• The profile follows upstream's final form: effort low through max with medium as the default, Ultrathink, and a fixed 1M context window. It also offers Ultracode, which Claude Code allows on every model with xhigh effort; upstream proposes the same in fix(models): Ultracode is offered on Sonnet 5, Sonnet 5.5 and Haiku 5.5 pingdotgg/t3code#17606.
• The haiku alias moves from Haiku 4.5 to Haiku 5.5, matching upstream. Haiku 4.5 stays as a legacy model.
• currentModels.claudeAgent lists Haiku 5.5 for releases that predate catalog discovery.
• Claude's text generation default becomes Haiku 5.5. This is the model used when Claude is the text generation provider without an explicit model, and when the server falls back to Claude because the selected provider is disabled. The global default stays Codex GPT-6 Luna; switching it to Claude needs an availability-aware fallback for users without a Claude subscription, which will be a separate change.
• The fork feature ledger records the Haiku 5.5 invariant.

Existing explicit text generation selections, such as Haiku 4.5, are not migrated.

Validation

• Loaded the bundled catalog: with Claude Code 2.1.292, Haiku 5.5 is hidden and the upgrade notice names v2.1.293; with 2.1.293 it is listed ahead of Haiku 4.5. haiku resolves to Haiku 5.5 and haiku-4.5 to Haiku 4.5. The default effort is medium, Ultracode is sent as xhigh, the API model ID is claude-haiku-5-5, and the context window is 1,000,000 tokens.
• Ran a title-generation request through Claude Code 2.1.296 with the same flags ClaudeTextGeneration uses (--model claude-haiku-5-5 --effort low, JSON schema output, no tools). It returned a valid structured title in about 2 seconds, and the CLI reported claude-haiku-5-5 with a 1M context window.
• In an isolated web dev server on fresh state, Settings > General still showed GPT-6 Luna · Low as the text generation model. Searching the model picker for "haiku" listed Claude Haiku 5.5 with a NEW badge, and selecting it showed Claude Haiku 5.5 · Medium.
• Claude model catalog, model manifest, Claude model options, server settings, and text generation tests pass, as do the contracts tests and typecheck.
• No screenshots: the preview panel's screenshot capture timed out in this session, so the UI checks above were read from the page.

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Written by an agent (Claude Code, claude-opus-5-5).

[github-actions]

Upstream divergence

Both sides are compared with upstream at the in-order tip 0fcd5f9061. Excludes .repos/ and pnpm-lock.yaml.

Measure	Base	This PR	Change
Upstream files the fork changes	1,227	1,227	0
Lines changed in them	66,851	66,895	+44
Upstream files the fork removes	37	37	0
Fork-only files	346	346	0
Fork-only lines	50,264	50,265	+1

Upstream files whose difference changes (2)

File	Change	Now differs by
apps/server/src/provider/model-manifest.json	+42	146 lines
packages/contracts/src/model.ts	+2	8 lines