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/plugin/ultrawork-model-override.test.ts

@@ -174,7 +174,7 @@ describe("resolveUltraworkOverride", () => {
     const output = createOutput("ulw do something")
 
     //#when
-    const result = resolveUltraworkOverride(config, "Sisyphus (Ultraworker)", output)
+    const result = resolveUltraworkOverride(config, "Sisyphus - Ultraworker", output)
 
     //#then
     expect(result).toEqual({ providerID: "anthropic", modelID: "claude-opus-4-6", variant: "max" })
@@ -408,7 +408,7 @@ describe("applyUltraworkModelOverrideOnMessage", () => {
     const tui = createMockTui()
 
     //#when
-    applyUltraworkModelOverrideOnMessage(config, "Sisyphus (Ultraworker)", output, tui)
+    applyUltraworkModelOverrideOnMessage(config, "Sisyphus - Ultraworker", output, tui)
 
     //#then
     expect(dbOverrideSpy).toHaveBeenCalledWith(