Add OMP provider support and model alias mapping

- Add OMP provider reading from ~/.omp/agent/sessions (same JSONL
  format as Pi, shared parser)
- Parameterize discoverSessionsInDir with provider name so sessions
  carry correct provider field
- Add BUILTIN_ALIASES for proxy model name variants (anthropic--claude-*
  double-dash format) that don't match LiteLLM keys
- Add model-alias CLI command for user-defined name mappings
- Wire setModelAliases into preAction after config load
- Add modelAliases field to CodeburnConfig
- Update README: OMP in provider table, model-alias section

tests/models.test.ts

@@ -0,0 +1,135 @@
+import { describe, it, expect, afterEach } from 'vitest'
+import { getModelCosts, getShortModelName, calculateCost, setModelAliases } from '../src/models.js'
+
+// Tests run without loadPricing — fallback pricing only.
+// setModelAliases resets between tests to avoid cross-contamination.
+afterEach(() => setModelAliases({}))
+
+describe('builtin aliases - getModelCosts', () => {
+  it('resolves anthropic--claude-4.6-opus', () => {
+    expect(getModelCosts('anthropic--claude-4.6-opus')).not.toBeNull()
+  })
+
+  it('resolves anthropic--claude-4.6-sonnet', () => {
+    expect(getModelCosts('anthropic--claude-4.6-sonnet')).not.toBeNull()
+  })
+
+  it('resolves anthropic--claude-4.5-opus', () => {
+    expect(getModelCosts('anthropic--claude-4.5-opus')).not.toBeNull()
+  })
+
+  it('resolves anthropic--claude-4.5-sonnet', () => {
+    expect(getModelCosts('anthropic--claude-4.5-sonnet')).not.toBeNull()
+  })
+
+  it('resolves anthropic--claude-4.5-haiku', () => {
+    expect(getModelCosts('anthropic--claude-4.5-haiku')).not.toBeNull()
+  })
+
+  it('resolves double-wrapped anthropic/anthropic--claude-4.6-opus', () => {
+    expect(getModelCosts('anthropic/anthropic--claude-4.6-opus')).not.toBeNull()
+  })
+
+  it('resolves double-wrapped anthropic/anthropic--claude-4.6-sonnet', () => {
+    expect(getModelCosts('anthropic/anthropic--claude-4.6-sonnet')).not.toBeNull()
+  })
+
+  it('resolves double-wrapped anthropic/anthropic--claude-4.5-haiku', () => {
+    expect(getModelCosts('anthropic/anthropic--claude-4.5-haiku')).not.toBeNull()
+  })
+
+  it('OMP opus resolves to same pricing as canonical claude-opus-4-6', () => {
+    expect(getModelCosts('anthropic--claude-4.6-opus')).toEqual(getModelCosts('claude-opus-4-6'))
+  })
+
+  it('OMP sonnet resolves to same pricing as canonical claude-sonnet-4-6', () => {
+    expect(getModelCosts('anthropic--claude-4.6-sonnet')).toEqual(getModelCosts('claude-sonnet-4-6'))
+  })
+
+  it('OMP haiku resolves to same pricing as canonical claude-haiku-4-5', () => {
+    expect(getModelCosts('anthropic--claude-4.5-haiku')).toEqual(getModelCosts('claude-haiku-4-5'))
+  })
+})
+
+describe('builtin aliases - getShortModelName', () => {
+  it('anthropic--claude-4.6-opus -> Opus 4.6', () => {
+    expect(getShortModelName('anthropic--claude-4.6-opus')).toBe('Opus 4.6')
+  })
+
+  it('anthropic--claude-4.6-sonnet -> Sonnet 4.6', () => {
+    expect(getShortModelName('anthropic--claude-4.6-sonnet')).toBe('Sonnet 4.6')
+  })
+
+  it('anthropic--claude-4.5-opus -> Opus 4.5', () => {
+    expect(getShortModelName('anthropic--claude-4.5-opus')).toBe('Opus 4.5')
+  })
+
+  it('anthropic--claude-4.5-sonnet -> Sonnet 4.5', () => {
+    expect(getShortModelName('anthropic--claude-4.5-sonnet')).toBe('Sonnet 4.5')
+  })
+
+  it('anthropic--claude-4.5-haiku -> Haiku 4.5', () => {
+    expect(getShortModelName('anthropic--claude-4.5-haiku')).toBe('Haiku 4.5')
+  })
+
+  it('anthropic/anthropic--claude-4.6-opus -> Opus 4.6', () => {
+    expect(getShortModelName('anthropic/anthropic--claude-4.6-opus')).toBe('Opus 4.6')
+  })
+})
+
+describe('user aliases via setModelAliases', () => {
+  it('user alias resolves for getModelCosts', () => {
+    setModelAliases({ 'my-internal-model': 'claude-sonnet-4-6' })
+    expect(getModelCosts('my-internal-model')).toEqual(getModelCosts('claude-sonnet-4-6'))
+  })
+
+  it('user alias resolves for getShortModelName', () => {
+    setModelAliases({ 'my-internal-model': 'claude-opus-4-6' })
+    expect(getShortModelName('my-internal-model')).toBe('Opus 4.6')
+  })
+
+  it('user alias overrides builtin', () => {
+    // Remap an OMP key to a different canonical target
+    setModelAliases({ 'anthropic--claude-4.6-opus': 'claude-sonnet-4-5' })
+    expect(getModelCosts('anthropic--claude-4.6-opus')).toEqual(getModelCosts('claude-sonnet-4-5'))
+  })
+
+  it('resetting aliases restores builtins', () => {
+    setModelAliases({ 'anthropic--claude-4.6-opus': 'claude-sonnet-4-5' })
+    setModelAliases({})
+    // Back to builtin: should resolve as opus pricing, not sonnet
+    expect(getModelCosts('anthropic--claude-4.6-opus')).toEqual(getModelCosts('claude-opus-4-6'))
+  })
+})
+
+describe('calculateCost - OMP names produce non-zero cost', () => {
+  it('calculates cost for anthropic--claude-4.6-opus', () => {
+    expect(calculateCost('anthropic--claude-4.6-opus', 1000, 200, 0, 0, 0)).toBeGreaterThan(0)
+  })
+
+  it('calculates cost for anthropic/anthropic--claude-4.6-sonnet', () => {
+    expect(calculateCost('anthropic/anthropic--claude-4.6-sonnet', 1000, 200, 0, 0, 0)).toBeGreaterThan(0)
+  })
+})
+
+describe('existing model names still resolve', () => {
+  it('canonical claude-opus-4-6', () => {
+    expect(getModelCosts('claude-opus-4-6')).not.toBeNull()
+  })
+
+  it('canonical claude-sonnet-4-5', () => {
+    expect(getModelCosts('claude-sonnet-4-5')).not.toBeNull()
+  })
+
+  it('date-stamped claude-sonnet-4-20250514', () => {
+    expect(getModelCosts('claude-sonnet-4-20250514')).not.toBeNull()
+  })
+
+  it('pinned claude-sonnet-4-6@20250929', () => {
+    expect(getModelCosts('claude-sonnet-4-6@20250929')).not.toBeNull()
+  })
+
+  it('anthropic/-prefixed anthropic/claude-opus-4-6', () => {
+    expect(getModelCosts('anthropic/claude-opus-4-6')).not.toBeNull()
+  })
+})