feat: Schema Visualizer, docs update & competitor comparison

* chore: add @xyflow/react, dagre, @types/dagre (Task 1)

* feat: add SchemaGraph, TableNode, GraphColumn, Relationship types (Task 2)

* feat: add SchemaGraph, TableNode, GraphColumn, Relationship Rust models (Task 3)

* feat: add cardinality color/label helpers and legend data (Task 4)

* feat: add schema_graph command skeleton with validation (Task 5)

* feat: add PostgreSQL schema graph query builder + cardinality inference (Task 6)

* feat: implement get_schema_graph for PostgreSQL + SQLite (Task 7)

* feat: add getSchemaGraph IPC wrapper (Task 8)

* feat: un-stub Schema Visualizer nav + add view branch placeholder (Task 9)

* feat: add SchemaVisualizerNode custom React Flow table card (Task 10)

* feat: add SchemaVisualizerPage with React Flow canvas (Task 11)

* feat: wire SchemaVisualizerPage + error handling + style polish (Tasks 12-14)

* perf: replace information_schema with pg_catalog for schema graph query (500x+ faster on remote PG)

* fix: add DB selector, ghost-style dropdowns, dark controls, minimap styling, attribution

* fix: always show schema selector, move attribution to top-left

* fix: SelectDropdown close on outside click works in React Flow (capture phase)

* style: remove border from attribution badge

* style: restore bg on attribution, no border

* fix: lower attribution z-index so dropdowns render above

* fix: ensure toolbar + dropdowns stack above canvas attribution

* feat: crow's foot markers on edges + collapsible legend

* fix: restore missing tableCount state (was overwritten by legendOpen)

* fix: move crow's foot marker defs inside ReactFlow SVG, remove duplicate external SVGs

* fix: inject crow's foot SVG markers into ReactFlow SVG via DOM ref

* fix: use hidden SVG before ReactFlow for crow's foot markers, remove DOM injection

* feat: custom CrowsFootEdge component with inline crow's foot markers

* feat: custom CrowsFootEdge with zero-or-one/zero-or-many notation + nullability-based cardinality

* fix: strip markers, use clean text labels only on edges

* fix: add SVG marker defs directly inside ReactFlow + url() references for crow's foot

* fix: use custom CrowsFootEdge with BaseEdge + inline SVG symbols (no marker defs needed)

* debug: add red/green circles at edge endpoints to verify custom edge renders

* fix: remove stale duplicate edge data, use clean data.startMarker/endMarker

* fix: use getSmoothStepPath offset points for correct tangent angle at endpoints

* fix: thicker strokeWidth, position at handle coords, use path tangents

* fix: use straight-line angle (not curve tangent) for marker rotation

* fix: compute marker positions directly with raw math, no SVG transforms

* fix: fixed-orientation symbols — | always vertical, crow's foot fans toward node

* fix: dead simple — | vertical line, ← or → horizontal crow's foot based on edge direction

* fix: increase marker gap to 12px so symbols aren't hidden behind handle dots

* fix: correct offset direction (away from card into gap), G=4

* fix: remove duplicate G offset inside Mark (was canceling out the call-site offset)

* fix: crow's foot back to fork shape — three lines converging to a tip

* fix: flip crow's foot direction

* fix: wider crow's foot spread (4→6)

* feat: add crow's foot symbols to relationship legend

* style: cleaner legend — horizontal edge with endpoint symbols + label

* feat: handles on both sides, edge builder picks closest side based on dagre layout

* fix: compute actual handle distances to pick shortest path

* revert: PK always left, FK always right — one handle per column only

* fix: lock edge marker direction via origRight, TB layout for horizontal spread, truncate long types

* fix: semi-transparent minimap mask, border stroke for viewport visibility

* feat: click edge to highlight (amber glow), all others dim to 15% opacity

* feat: legend highlights matching cardinality row when edge is clicked

* fix: crow's foot symbols now read color from edge style (amber when highlighted)

* fix: highlighted edge gets zIndex 1000 to render on top

* fix: folder empty message now checks unfiltered store, shows filter hint when connections exist but filtered out

* feat: flat SVG DB icons from simple-icons (PostgreSQL, MySQL, SQLite, Redis) replacing emoji

* chore: add *.db, *.sqlite, *.sqlite3 to .gitignore

* docs: update README with 3-way competitor comparison + current roadmap; update AGENTS.md schema visualizer status

src/lib/dbIcons.tsx

@@ -0,0 +1,59 @@
+import { siPostgresql, siMysql, siSqlite, siRedis } from "simple-icons";
+import type { DbType } from "./types";
+
+// Brand colors from simple-icons
+const DB_COLORS: Record<DbType, string> = {
+  postgresql: `#${siPostgresql.hex}`,
+  mysql: `#${siMysql.hex}`,
+  redis: `#${siRedis.hex}`,
+  sqlite: `#${siSqlite.hex}`,
+};
+
+// SVG path data for each DB icon
+const DB_PATHS: Record<DbType, string> = {
+  postgresql: siPostgresql.path,
+  mysql: siMysql.path,
+  redis: siRedis.path,
+  sqlite: siSqlite.path,
+};
+
+export const DB_LABELS: Record<DbType, string> = {
+  postgresql: "PostgreSQL",
+  mysql: "MySQL",
+  redis: "Redis",
+  sqlite: "SQLite",
+};
+
+interface DbIconProps {
+  type: DbType;
+  size?: number;
+  className?: string;
+}
+
+export function DbIcon({ type, size = 20, className }: DbIconProps) {
+  const path = DB_PATHS[type];
+  const color = DB_COLORS[type];
+  if (!path) return <span className="text-lg">❓</span>;
+
+  return (
+    <svg
+      role="img"
+      viewBox="0 0 24 24"
+      width={size}
+      height={size}
+      className={className}
+      fill={color}
+      xmlns="http://www.w3.org/2000/svg"
+    >
+      <path d={path} />
+    </svg>
+  );
+}
+
+// Keep backward compat for any legacy emoji usage
+export const DB_ICONS: Record<DbType, string> = {
+  postgresql: "🐘",
+  mysql: "🐬",
+  redis: "⚡",
+  sqlite: "🗄️",
+};