root/docs: index mbproxy's post-Phase-9/10/11 capabilities

Multiplexing, read coalescing, and opt-in response caching change what someone might
come to mbproxy for, so the root index now names them alongside BCD rewriting.

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

CLAUDE.md

@@ -23,7 +23,7 @@ When in doubt about where content belongs, default to pushing it deeper. `DOCS-G
 - [`graccesscli/`](graccesscli/README.md) — `.NET Framework 4.8 / x86` CliFx-based CLI for automating Galaxy configuration through the ArchestrA GRAccess COM interop.
 - [`grdb/`](grdb/README.md) — SQL/DDL exploration of the Galaxy Repository SQL database (queries, schema, hierarchy/tag-name translation).
 - [`histdb/`](histdb/README.md) — LLM-oriented reference for AVEVA Historian retrieval (extension tables, `wwXxx` time-domain extensions, retrieval modes/options, alarm-event SQL, REST API). Distilled from the official Historian Retrieval Guide.
-- [`mbproxy/`](mbproxy/README.md) — `.NET 10` Windows Service that proxies Modbus TCP inline and rewrites BCD-encoded registers bidirectionally for a fleet of ~54 DL205/DL260 PLCs.
+- [`mbproxy/`](mbproxy/README.md) — `.NET 10` Windows Service that proxies Modbus TCP for a fleet of ~54 DL205/DL260 PLCs: inline bidirectional BCD rewriting, single-backend-conn TxId multiplexing (lifts the H2-ECOM100 4-client cap), in-flight read coalescing, and opt-in per-tag response caching.
 - [`mxaccesscli/`](mxaccesscli/README.md) — `.NET Framework 4.8 / x86` CliFx-based CLI for reading, writing, and subscribing to System Platform tags via the **MxAccess** COM proxy (`LMXProxyServerClass`).
 - [`secrets/`](secrets/README.md) — Self-hosted Infisical CLI + `secret` PowerShell helper for fetching credentials from `https://infisical.dohertylan.com` instead of inlining plaintext.
 
@@ -36,7 +36,7 @@ When in doubt about where content belongs, default to pushing it deeper. `DOCS-G
 | Automate Galaxy configuration via GRAccess COM (CLI usage, session daemon, mutations, LLM integration) | [`graccesscli/README.md`](graccesscli/README.md) |
 | Galaxy Repository SQL — connect, schema, hierarchy queries, contained-name ↔ tag-name translation | [`grdb/README.md`](grdb/README.md) |
 | AVEVA Historian retrieval — SQL via `INSQL`, `wwXxx` extensions, retrieval modes/options, alarm/event SQL, REST API | [`histdb/README.md`](histdb/README.md) |
-| Proxy Modbus TCP inline with bidirectional BCD rewriting for DL205/DL260 fleet (install, ops, status page) | [`mbproxy/README.md`](mbproxy/README.md) |
+| Proxy Modbus TCP for DL205/DL260 fleet — BCD rewriting, TxId multiplexing, read coalescing, opt-in response cache, install/ops, status page | [`mbproxy/README.md`](mbproxy/README.md) |
 | Read / write / subscribe to System Platform tags via MxAccess (timeouts, error categories, JSON envelope) | [`mxaccesscli/README.md`](mxaccesscli/README.md) |
 | Fetch credentials from Infisical instead of using plaintext (`secret <KEY>` helper, env vars, identity reuse) | [`secrets/README.md`](secrets/README.md) |