feat(prompt): configurable per-platform system-prompt hint overrides

Add platform_hints config so an admin can append to or replace Hermes'
built-in platform hint for a single messaging platform (WhatsApp, Slack,
Telegram, ...) without affecting other platforms. Enables enterprise
managed profiles to steer platform-aware skills (e.g. invoke a custom
table-formatting skill on WhatsApp where Markdown tables don't render)
while leaving Telegram/Slack/CLI behavior unchanged.

- hermes_cli/config.py: document platform_hints in DEFAULT_CONFIG
- agent/agent_init.py: load platform_hints -> agent._platform_hint_overrides
- agent/system_prompt.py: _resolve_platform_hint() applies append/replace
  (replace wins; bare string = append shorthand); defensive on bad config
- tests: 16 cases covering append/replace/shorthand/isolation/malformed

Override only affects the platform-hint segment of the system prompt;
SOUL/context/memory tiers and general instructions are unchanged.

scripts/release.py

@@ -45,6 +45,7 @@ ACP_REGISTRY_MANIFEST = REPO_ROOT / "acp_registry" / "agent.json"
 
 # Auto-extracted from noreply emails + manual overrides
 AUTHOR_MAP = {
+    "victor@rocketfueldev.com": "victor-kyriazakos",
     "286497132+srojk34@users.noreply.github.com": "srojk34",
     "59806492+sitkarev@users.noreply.github.com": "sitkarev",
     "zheng@omegasys.eu": "omegazheng",