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-handlers/agent-override-protection.ts

@@ -1,4 +1,5 @@
 const PARENTHETICAL_SUFFIX_PATTERN = /\s*(\([^)]*\)\s*)+$/u
+const DASH_SUFFIX_PATTERN = /\s+-\s+.+$/u
 const ZERO_WIDTH_CHARACTERS_PATTERN = /[\u200B\u200C\u200D\uFEFF]/g
 
 export function normalizeProtectedAgentName(agentName: string): string {
@@ -7,6 +8,7 @@ export function normalizeProtectedAgentName(agentName: string): string {
     .trim()
     .toLowerCase()
     .replace(PARENTHETICAL_SUFFIX_PATTERN, "")
+    .replace(DASH_SUFFIX_PATTERN, "")
     .replace(/[-_]/g, "")
     .trim()
 }