docs: lead with what DeepSQL does, matched to the site hero

Rewrite "What it does" around the product framing on deepsql.ai: a 24/7 DBA and data engineer that answers BI questions, fixes slow queries and watches your schema, all from one shared brain. Move the section above Quick start so the README reads intro, capabilities, install. Promote the MCP server subsection to a top-level heading now that its parent moved.

Author: venkateshsakamuri-lab

README.md

@@ -17,6 +17,36 @@ reasoning behind it.
 
 ---
 
+## What it does
+
+Your 24/7 DBA and data engineer. It answers BI questions, fixes slow queries, and watches
+your schema — all from one shared brain.
+
+- **Answers BI questions.** Ask in plain English. The agent loads your business context,
+  resolves the schema, drafts and validates SQL, then executes it read-only — with every
+  step you can inspect. The hand-written SQL editor is the only path that can mutate, and
+  only for a confirming admin.
+- **Fixes slow queries.** Reads `pg_stat_statements` or the MySQL slow log, groups queries
+  by fingerprint, ranks them by cost, and flags regressions against their baseline.
+- **Index recommendations.** Advises, and can apply them for you — `CREATE INDEX
+  CONCURRENTLY` on PostgreSQL, so no table lock.
+- **Watches your schema.** Tracks what changed and what needs attention, so drift surfaces
+  before it breaks a query or a dashboard.
+- **A brain that knows your business.** Teach it your metrics, rules and conventions once —
+  MRR, active accounts, currency handling — and every query, dashboard and recommendation
+  uses the same governed definitions.
+- **Dashboards without the analyst backlog.** An agent writes a single self-contained HTML
+  document, rendered in a sandboxed iframe with no network access. It reads data only
+  through a read-only query bridge back to the backend — the agent gets creative freedom,
+  the database keeps its guard rail.
+- **Ask it from anywhere.** The web UI, your terminal, or a Slack channel. The MCP server
+  gives coding agents (Claude Code, Cursor, Codex, Claude Desktop) the same capabilities
+  over stdio.
+- **Postgres and MySQL, in your infra.** One dialect registry, read-only execution, and SSH
+  tunnelling to reach databases behind a bastion.
+
+---
+
 ## Quick start
 
 There are no prebuilt images and no container registry. Docker Compose builds the backend
@@ -143,25 +173,7 @@ version), `_USE_RESPONSES_API` (`true` / `false` / `auto`).
 
 ---
 
-## What it does
-
-- **Ask in English.** Schema questions, business questions, "why is this slow" questions.
-  SQL that the assistant or an agent generates is validated and executed read-only; the
-  hand-written SQL editor is the only path that can mutate, and only for a confirming admin.
-- **Slow query analysis.** Ingests and groups slow queries, attributes cost, and explains
-  what is actually expensive.
-- **Index recommendations.** Advises, and can apply them for you — `CREATE INDEX
-  CONCURRENTLY` on PostgreSQL, so no table lock.
-- **Generated dashboards.** An agent writes a single self-contained HTML document, rendered
-  in a sandboxed iframe with no network access. It reads data only through a read-only query
-  bridge back to the backend — the agent gets creative freedom, the database keeps its guard
-  rail.
-- **MCP server.** Gives coding agents (Claude Code, Cursor, Codex, Claude Desktop) the same
-  capabilities over stdio.
-- **SSH tunnelling.** Reach databases behind a bastion without exposing them.
-- **PostgreSQL and MySQL**, behind one dialect registry.
-
-### MCP server
+## MCP server
 
 The server lives in `mcp/` and exposes 44 tools that wrap the backend API, so agents reuse
 the same orchestration, retrieval and guardrails instead of getting raw database