feat(hermes): Hermes Agent harness support, rebased to a Hermes-only diff

Rebase of PR #1922 onto current dev: the ~14 files of v6.1.0-era
codex/release drift are dropped, the porting-guide edits (stale against
the post-prune rewrite, no Hermes content) are dropped, and the Hermes
surface is kept intact: .hermes-plugin/ (on_session_start bootstrap
injection), tests/hermes/ (20 tests, passing), docs/README.hermes.md,
references/hermes-tools.md, the Platform Adaptation row, README section,
and Python ignores.

Known open items from review, unchanged by this rebase: the injection
mechanism uses ctx.inject_message from on_session_start, which the
official plugin guide does not document (pre_llm_call returning
{"context": ...} is the sanctioned path), skills are not registered via
ctx.register_skill, and the acceptance transcript predates the fix.

Co-authored-by: kumarabd <kumarabd@users.noreply.github.com>

.hermes-plugin/INSTALL.md

@@ -0,0 +1,30 @@
+# Hermes Agent — Superpowers Plugin
+
+## Install
+
+```bash
+hermes plugins install obra/superpowers --enable
+```
+
+Restart any active Hermes sessions after installing.
+
+## Smoke check
+
+Start a new session and send:
+> What are your superpowers?
+
+The model should describe brainstorming, TDD, debugging, and planning skills.
+If it doesn't, the bootstrap isn't loading — reinstall and restart.
+
+## Acceptance test
+
+Send in a fresh session:
+> Let's make a react todo list
+
+The `brainstorming` skill must trigger and run its flow before any code is written.
+
+## Uninstall
+
+```bash
+hermes plugins remove superpowers
+```