Feat/bankr provider (#888)

* feat(provider): add Bankr LLM Gateway support

Add Bankr as an OpenAI-compatible provider preset with dedicated env vars:
- BNKR_API_KEY, BANKR_BASE_URL, BANKR_MODEL
- Uses X-API-Key header instead of Authorization Bearer
- Base URL: https://llm.bankr.bot/v1
- Default model: claude-opus-4.6

Changes:
- Add 'bankr' to VALID_PROVIDERS and provider flag handling
- Add buildBankrProfileEnv() with env key registration
- Add Bankr detection in startup screen and provider discovery
- Map Bankr env vars to OpenAI-compatible vars in shim
- Add Bankr preset to ProviderManager (alphabetical order)
- Update PRESET_ORDER test to include Bankr

Co-Authored-By: OpenClaude <openclaude@gitlawb.com>

* fixup(provider): address Bankr PR review feedback

1. Map BNKR_API_KEY → OPENAI_API_KEY in providerFlag.ts so
   --provider bankr works with BNKR_API_KEY in non-interactive startup.

2. Remove unconditional BANKR_MODEL read from model.ts; it maps to
   OPENAI_MODEL via providerFlag.ts and openaiShim.ts, preventing
   cross-provider leakage.

3. Use X-API-Key for Bankr model discovery in openaiModelDiscovery.ts
   and providerDiscovery.ts, matching chat request auth.

Co-Authored-By: OpenClaude <openclaude@gitlawb.com>

---------

Co-authored-by: OpenClaude <openclaude@gitlawb.com>

src/utils/providerProfile.ts

@@ -70,6 +70,9 @@ const PROFILE_ENV_KEYS = [
   'MISTRAL_BASE_URL',
   'MISTRAL_API_KEY',
   'MISTRAL_MODEL',
+  'BANKR_BASE_URL',
+  'BNKR_API_KEY',
+  'BANKR_MODEL',
 ] as const
 
 const SECRET_ENV_KEYS = [
@@ -80,6 +83,7 @@ const SECRET_ENV_KEYS = [
   'NVIDIA_API_KEY',
   'MINIMAX_API_KEY',
   'MISTRAL_API_KEY',
+  'BNKR_API_KEY',
 ] as const
 
 export type ProviderProfile = 'openai' | 'ollama' | 'codex' | 'gemini' | 'atomic-chat' | 'nvidia-nim' | 'minimax' | 'mistral'
@@ -105,6 +109,9 @@ export type ProfileEnv = {
   MISTRAL_BASE_URL?: string
   MISTRAL_API_KEY?: string
   MISTRAL_MODEL?: string
+  BANKR_BASE_URL?: string
+  BNKR_API_KEY?: string
+  BANKR_MODEL?: string
 }
 
 export type ProfileFile = {
@@ -121,7 +128,8 @@ type SecretValueSource = Partial<
     | 'GOOGLE_API_KEY'
     | 'NVIDIA_API_KEY'
     | 'MINIMAX_API_KEY'
-    | 'MISTRAL_API_KEY',
+    | 'MISTRAL_API_KEY'
+    | 'BNKR_API_KEY',
     string | undefined
   >
 >
@@ -395,6 +403,42 @@ export function buildMistralProfileEnv(options: {
   return env
 }
 
+export function buildBankrProfileEnv(options: {
+  model?: string | null
+  baseUrl?: string | null
+  apiKey?: string | null
+  processEnv?: NodeJS.ProcessEnv
+}): ProfileEnv | null {
+  const processEnv = options.processEnv ?? process.env
+  const key = sanitizeApiKey(options.apiKey ?? processEnv.BNKR_API_KEY)
+  if (!key) {
+    return null
+  }
+
+  const env: ProfileEnv = {
+    BNKR_API_KEY: key,
+    BANKR_MODEL:
+      sanitizeProviderConfigValue(options.model, { BNKR_API_KEY: key }) ||
+      sanitizeProviderConfigValue(
+        processEnv.BANKR_MODEL,
+        { BNKR_API_KEY: key },
+      ) ||
+      'claude-opus-4.6',
+  }
+
+  const baseUrl =
+    sanitizeProviderConfigValue(options.baseUrl, { BNKR_API_KEY: key }) ||
+    sanitizeProviderConfigValue(
+      processEnv.BANKR_BASE_URL,
+      { BNKR_API_KEY: key },
+    )
+  if (baseUrl) {
+    env.BANKR_BASE_URL = baseUrl
+  }
+
+  return env
+}
+
 export function buildCodexOAuthProfileEnv(
   tokens: {
     accessToken: string