docs: restructure around source-of-truth pages

- CONTEXT.md glossary
- README reduced to intro, quickstart and doc index
- new architecture.md, gateway.md (from proxy-key-onboarding.md),
  operations.md; network-access.md rewritten
- coding-cli-setup: stale OMNIROUTE_PORT:-4000 endpoint, terms and
  duplicated per-slot/classifier explanations fixed
- research/README.md index; proxy-request-priority.md moved there as
  superseded

Every doc names keys instead of restating values and links its source.

Refs #55 (#56, #57, #59, #60)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/coding-cli-setup/claude-code.md

@@ -2,12 +2,14 @@
 
 [← back to overview](index.md)
 
+> **Source of truth:** [Claude Code's docs](https://docs.claude.com/en/docs/claude-code/overview) for config keys; the [overview](index.md) for the gateway endpoint and context size. If this page disagrees with them, they win.
+
 Claude Code speaks the **Anthropic Messages API** — point it at the gateway's unified endpoint, not llama.cpp directly:
 
 ```bash
-export ANTHROPIC_BASE_URL=http://<ai-box>:${OMNIROUTE_PORT:-4000}
-export ANTHROPIC_API_KEY=<claude-code-cli virtual key>
+export ANTHROPIC_BASE_URL=http://<server>:<OMNIROUTE_API_PORT>
+export ANTHROPIC_API_KEY=<claude-code-cli API key>
 claude
 ```
 
-Requires llama.cpp's `--jinja` flag (already set in `docker-compose.yml`) — without it, tool-use requests fail outright.
+Relies on the backend's `--jinja` flag ([architecture → llama-server](../architecture.md#llama-server)).