docs(readme): update assistant roster, prompt layers, repo structure

- Update assistant lists (added Shawn, Watson, David, CASE, AWS SA; modified Scotty/Harper roles)
- Reflect new architecture layers: Tool Prompt Snippets and Shared Context
- Align repository structure diagram with current filesystem layout

docs/tools/gitea.md

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+# Gitea
+
+> Self-hosted Git repository management.
+
+- **MCP server name:** `gitea` (runs on `miranda.incus` in the lab; talks to the Gitea instance at `git.helu.ca`)
+- **Prompt snippet:** [prompts/tools/gitea.md](../../prompts/tools/gitea.md)
+
+## What It Is
+
+Gitea is the user's self-hosted Git server. The MCP integration lets agents read repos, list issues, work with pull requests, and inspect commits without shelling out to `git`.
+
+## What It's Good For
+
+- Reading code from any koios-org-or-user-owned repo without cloning it locally
+- Listing or inspecting issues and pull requests
+- Checking commit history, blame, file contents at a specific revision
+- Cross-repo lookups when an agent needs context from a repo it isn't sitting inside
+
+## What It's Not Good For
+
+- Code search across many repos at once — Gitea MCP is per-repo; for broad searches use Argos with site-scoped queries
+- Heavy edit workflows — for active development, work in a local clone via Kernos; Gitea MCP is mostly read-oriented in practice
+- Repos hosted on GitHub — use the GitHub MCP for those
+
+## Known Gotchas
+
+- **Repos are user-scoped, not org-scoped.** Per Robert's convention, repos on `git.helu.ca` are owned by his personal user account, not an org. Default secrets/variables/permissions accordingly.
+- **Gitea Actions vars vs. secrets.** When configuring CI, prefer user-scope (not org-scope) on this instance.