Add FirePass provider support for Kimi K2.5 Turbo

- Add new 'firepass' provider type alongside anthropic, openai, openrouter
- FirePass uses Fireworks AI's endpoint for Kimi K2.5 Turbo model
- Subscription billing model ($7/week) with 256K context window
- Anthropic API compatible (uses Anthropic SDK with custom baseURL)

Changes:
- providers.ts: Add firepass detection and base URL handling
- auth.ts: Add FirePass API key management (FIREPASS_API_KEY or FIREWORKS_API_KEY)
- config.ts: Add firepassApiKey and firepass auth provider
- client.ts: Add firepass client creation with custom baseURL
- http.ts: Add firepass auth headers
- modelStrings.ts: Return Kimi K2.5 Turbo model ID for firepass
- model.ts: Add Kimi display name handling and default model logic
- modelOptions.ts: Simplified model picker for firepass (Kimi K2.5 Turbo only)
- status.tsx: Display FirePass in status bar
- login.tsx: Add FirePass option to provider selection
- FirepassLoginFlow.tsx: New component for FirePass login flow

Usage:
1. Run /login and select "FirePass"
2. Enter your Fireworks API key
3. Model picker shows Kimi K2.5 Turbo

src/components/FirepassLoginFlow.tsx

@@ -0,0 +1,89 @@
+import * as React from 'react'
+import { useState } from 'react'
+import { Box, Text } from '../ink.js'
+import { saveFirepassApiKey } from '../utils/auth.js'
+import { Spinner } from './Spinner.js'
+import TextInput from './TextInput.js'
+
+type FirepassLoginFlowProps = {
+  onDone: () => void
+  startingMessage?: string
+}
+
+export function FirepassLoginFlow({
+  onDone,
+  startingMessage,
+}: FirepassLoginFlowProps): React.ReactNode {
+  const [isBusy, setIsBusy] = useState(false)
+  const [status, setStatus] = useState<string | null>(null)
+  const [inputValue, setInputValue] = useState('')
+  const [cursorOffset, setCursorOffset] = useState(0)
+
+  async function handleSubmit(value: string): Promise<void> {
+    const trimmed = value.trim()
+    if (!trimmed) {
+      return
+    }
+
+    setIsBusy(true)
+    setStatus(null)
+    try {
+      await saveFirepassApiKey(trimmed)
+      onDone()
+    } catch (error) {
+      setStatus(error instanceof Error ? error.message : String(error))
+    } finally {
+      setIsBusy(false)
+    }
+  }
+
+  if (isBusy) {
+    return (
+      <Box flexDirection="column" gap={1}>
+        <Box>
+          <Spinner />
+          <Text>Configuring FirePass login for Better-Clawd...</Text>
+        </Box>
+        <Text dimColor={true}>
+          FirePass uses your Fireworks API key with the Anthropic-compatible
+          endpoint at `https://api.fireworks.ai/inference`.
+        </Text>
+      </Box>
+    )
+  }
+
+  return (
+    <Box flexDirection="column" gap={1}>
+      <Text>
+        {startingMessage ??
+          'Better-Clawd can use FirePass with your Fireworks API key.'}
+      </Text>
+      <Text dimColor={true}>
+        FirePass provides subscription-based access to Kimi K2.5 Turbo with no
+        per-token charges. Get FirePass at{' '}
+        <Text color="cyan">https://app.fireworks.ai/fire-pass</Text>
+      </Text>
+      <Box>
+        <Text>Paste your Fireworks API key:</Text>
+        <TextInput
+          value={inputValue}
+          onChange={setInputValue}
+          onSubmit={handleSubmit}
+          onExit={() => {
+            setInputValue('')
+            setCursorOffset(0)
+          }}
+          cursorOffset={cursorOffset}
+          onChangeCursorOffset={setCursorOffset}
+          columns={72}
+          mask="*"
+        />
+      </Box>
+      {status ? <Text color="error">{status}</Text> : null}
+      <Text dimColor={true}>
+        Press <Text bold={true}>Enter</Text> to save, or <Text bold={true}>Esc</Text>{' '}
+        to cancel.
+      </Text>
+    </Box>
+  )
+}