fix(agent-names): use HTTP-header-safe display names and config keys for API calls (#3138)

Display names with parentheses like 'Atlas (Plan Executor)' cause HTTP
header validation errors in x-opencode-agent-name. This was blocking
Atlas/Prometheus from working via /start-work and auto-retry.

Changes:
- Display names: parens -> dashes ('Atlas - Plan Executor')
- Hooks (start-work, no-hephaestus-non-gpt, no-sisyphus-gpt): use
  config keys ('atlas', 'sisyphus', 'hephaestus') for agent API fields
- auto-retry: use config key instead of display name for promptAsync
- agent-override-protection: handle dash-suffix normalization
- Updated all test expectations to match new format

Closes #3138

src/hooks/prometheus-md-only/index.test.ts

@@ -94,7 +94,7 @@ describe("prometheus-md-only", () => {
 
     test("should enforce md-only restriction for Prometheus display name Plan Builder", async () => {
       //#given
-      setupMessageStorage(TEST_SESSION_ID, "Prometheus (Plan Builder)")
+      setupMessageStorage(TEST_SESSION_ID, "Prometheus - Plan Builder")
       const hook = createPrometheusMdOnlyHook(createMockPluginInput())
       const input = {
         tool: "Write",