docs(v2.3): document how agents see Scarf projects

Three doc updates covering the AGENTS.md context-injection
pattern introduced in the previous commit.

CLAUDE.md — new "Project-scoped chat + Scarf-managed AGENTS.md
context (v2.3)" subsection under Project Templates. Covers:

- The session-project sidecar at ~/.hermes/scarf/session_project_map.json
  (why it exists, what manages it)
- How Hermes picks up project context: cwd-based auto-load of the
  first matching context file (priority order, 20KB cap)
- Exact marker format and block shape
- Invariants that future edits must preserve: secret-safe,
  idempotent, bounded-region, non-fatal, refresh-before-session-start
  ordering
- Template-author contract: leave the region alone, put
  instructions below
- Known caveat: parent-directory `.hermes.md` shadowing (deferred
  to v2.4)

scarf-template-author SKILL.md — new pitfall bullet in the
"Common pitfalls" checklist telling scaffolding agents to
preserve the `<!-- scarf-project -->` region and put template-
specific instructions below it. Rebuilt the bundle so installs
from the catalog pick up the guidance; regenerated catalog.json.

Wiki update (Project-Templates page) lands next via scripts/wiki.sh.

93/93 Swift + 24/24 Python tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

templates/catalog.json

@@ -69,8 +69,8 @@
         "name": "Alan Wizemann",
         "url": "https://github.com/awizemann"
       },
-      "bundleSha256": "bebc30551dc92717da96608bbdf448c5d7c47bdb66807037b139a242ef8c3b74",
-      "bundleSize": 14423,
+      "bundleSha256": "56ab97eeb45ab7b9e6715ce9c88ec2c953bf795698cd19628d300d5b8cffd475",
+      "bundleSize": 14610,
       "category": "developer-tools",
       "config": null,
       "contents": {