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/tools/delegate-task/zauc-mocks-subagent-resolver/subagent-resolver.test.ts

@@ -675,7 +675,7 @@ describe("resolveSubagentExecution - agent name sanitization", () => {
     })
     const args = createBaseArgs({ subagent_type: "\\hephaestus\\" })
     const executorCtx = createExecutorContext(async () => ([
-      { name: "Hephaestus (Deep Agent)", mode: "subagent", model: "openai/gpt-5.3-codex" },
+      { name: "Hephaestus - Deep Agent", mode: "subagent", model: "openai/gpt-5.3-codex" },
     ]))
 
     //#when
@@ -683,7 +683,7 @@ describe("resolveSubagentExecution - agent name sanitization", () => {
 
     //#then
     expect(result.error).toBeUndefined()
-    expect(result.agentToUse).toBe("Hephaestus (Deep Agent)")
+    expect(result.agentToUse).toBe("Hephaestus - Deep Agent")
     cacheSpy.mockRestore()
   })