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/services/api/openaiShim.ts

@@ -1594,10 +1594,18 @@ class OpenAIShimMessages {
         (hostname.includes('cognitiveservices') || hostname.includes('openai') || hostname.includes('services.ai'))
     } catch { /* malformed URL — not Azure */ }
 
+    let isBankr = false
+    try {
+      isBankr = request.baseUrl.toLowerCase().includes('bankr')
+    } catch { /* malformed URL — not Bankr */ }
+
     if (apiKey) {
       if (isAzure) {
         // Azure uses api-key header instead of Bearer token
         headers['api-key'] = apiKey
+      } else if (isBankr) {
+        // Bankr uses X-API-Key header instead of Bearer token
+        headers['X-API-Key'] = apiKey
       } else {
         headers.Authorization = `Bearer ${apiKey}`
       }
@@ -2152,6 +2160,17 @@ export function createOpenAIShimClient(options: {
       process.env.GITHUB_TOKEN ?? process.env.GH_TOKEN ?? ''
   }
 
+  // Map Bankr env vars to OpenAI-compatible ones when present
+  if (process.env.BNKR_API_KEY && !process.env.OPENAI_API_KEY) {
+    process.env.OPENAI_API_KEY = process.env.BNKR_API_KEY
+  }
+  if (process.env.BANKR_BASE_URL && !process.env.OPENAI_BASE_URL) {
+    process.env.OPENAI_BASE_URL = process.env.BANKR_BASE_URL
+  }
+  if (process.env.BANKR_MODEL && !process.env.OPENAI_MODEL) {
+    process.env.OPENAI_MODEL = process.env.BANKR_MODEL
+  }
+
   const beta = new OpenAIShimBeta({
     ...(options.defaultHeaders ?? {}),
   }, options.reasoningEffort, options.providerOverride)