docs: add service README.md files + update AGENTS.md decisions

- Create README.md for 25+ service modules with container info, API surface, storage
- Document attestor-tileproxy separation rationale (air-gap network isolation)
- Document opsmemory-advisoryai separation rationale (resource isolation, blast radius)
- Update Timeline AGENTS.md with merged indexer info

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/BinaryIndex/README.md

@@ -0,0 +1,18 @@
+# BinaryIndex
+
+**Container(s):** stellaops-binaryindex-web, stellaops-symbols
+**Slot:** 36 (binaryindex), 38 (symbols)  |  **Port:** 8080  |  **Consumer Group:** binaryindex, symbols
+**Resource Tier:** light
+
+## Purpose
+The BinaryIndex service provides binary vulnerability detection through build-ID and binary signature resolution, golden set management, delta signature tracking, and VEX bridge integration. It includes a caching layer (Valkey) for resolution results. The Symbols server provides symbol recovery and debug information lookup for binary analysis.
+
+## API Surface
+- `binaryindex` (via Router) — binary resolution (build-ID/signature lookup), golden set queries, delta signature management, VEX bridge queries, telemetry
+- `symbols` (via Router) — symbol file upload/download, debug info queries
+
+## Storage
+PostgreSQL (via `ConnectionStrings:Default`); Valkey for resolution cache; in-memory golden set and vulnerability stores
+
+## Background Workers
+None