Add drawio-main skill (renamed from drawio-main-v1)

Draw.io diagram generation and analysis skill: mandatory layout and
style rules, XML reference, negative-space companion diagrams, and
the drawio-tools TypeScript CLI with 12 analysis/validation actions.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -1,2 +1,139 @@
 # drawio-main
-Agent Skill for creating and validating draw.io diagrams via layout rules and a validation CLI.
+
+CLI tools for programmatic analysis and verification of `.drawio` files.
+
+Built with TypeScript using [`@maxgraph/core`](https://github.com/maxGraph/maxGraph) — the official TypeScript successor to mxGraph (the library draw.io is built on) — for accurate XML parsing and absolute coordinate resolution.
+
+## Stack
+
+| Concern | Choice |
+|---|---|
+| Language | TypeScript (ESM, `NodeNext`) |
+| Package manager | pnpm |
+| XML / model parsing | `@maxgraph/core` v0.23 |
+| Node.js DOM polyfill | `jsdom` |
+| `<mxfile>` decoding | `pako` (base64 + deflate) |
+| Output | YAML (via `js-yaml`) |
+
+## Install
+
+```bash
+pnpm install
+```
+
+## Build
+
+```bash
+pnpm run build
+# compiled output → dist/
+```
+
+## Usage
+
+```bash
+node dist/cli/commands.js --file diagram.drawio --action <action> [--page <index>]
+
+# or via tsx (no build step)
+pnpm dev --file diagram.drawio --action <action>
+```
+
+Output is always YAML to stdout.
+
+## Actions
+
+### Inventory
+
+#### `summary`
+
+Parses **all pages (tabs)** in the `.drawio` file and returns a full inventory of shapes and edges per page. Delegates per-page data to the same logic as `page-summary`.
+
+**Output:** `pageCount`, `pages[]` (each page has the same structure as `page-summary`)
+
+---
+
+#### `page-summary`
+
+Parses a **single page**. Use `--page <index>` (0-based, default `0`).
+
+**Output:** `pageCount`, `pageIndex`, `pageName`, `page` (width/height), `summary` (shapeCount, edgeCount, contentRight, contentBottom), `shapes[]`, `edges[]`
+
+---
+
+#### `page-hierarchy`
+
+Reads `parentId` from each shape and builds a **recursive containment tree**:
+- Depth 0 — layers / top-level containers (direct children of the canvas)
+- Depth 1 — subsystems / groups inside a layer
+- Depth 2+ — leaf components and nested elements
+
+**Output:** `summary` (totalShapes, maxDepth, depthCounts), `tree[]` (recursive: id, label, depth, childCount, children[])
+
+---
+
+#### `page-connectors-summary`
+
+Returns a summary of all **connectors (edges)** on the page, classified by type and connectivity.
+
+Connector types: `directed` (both endpoints connected), `partial` (one missing), `floating` (both missing)
+
+**Output:** `summary` (total, directed, partial, floating, labelled, unlabelled, withWaypoints, straight), `connectors[]` (id, label, sourceId, sourceLabel, targetId, targetLabel, waypointCount, type)
+
+---
+
+### Validation
+
+#### `page-connectors-validation`
+
+Detects two categories of layout defects on the first page:
+1. **Connector-shape overlaps** — a connector segment passes through a shape it is not connected to
+2. **Connector crossings** — two connectors intersect at an interior point
+
+Uses 2 px tolerance. **Output:** `summary` (connectorShapeOverlaps, connectorCrossings, totalIssues), `issues[]`
+
+---
+
+#### `page-labels-validation`
+
+Validates shape labels and flags:
+1. **empty_label** — shape has no label (whitespace counts as empty)
+2. **duplicate_label** — two or more shapes share the same label
+3. **long_label** — label exceeds 80 characters
+
+Edges/connectors are excluded. **Output:** `config` (maxLabelLength), `summary` (emptyLabels, duplicateLabels, longLabels, totalIssues), `issues[]`
+
+---
+
+#### `page-shape-bbox-validation`
+
+Detects shapes whose **bounding boxes overlap** each other. Parent-child containment is intentional and is **not** flagged. Uses 2 px tolerance.
+
+**Output:** `summary` (totalShapes, overlappingPairs), `issues[]` (shapeAId, shapeALabel, shapeBId, shapeBLabel, overlapX, overlapY)
+
+---
+
+#### `page-orphans`
+
+Finds disconnected elements:
+1. **isolated_shape** — shape with no edges connected to it
+2. **dangling_connector** — edge missing its source and/or target shape
+
+**Output:** `summary` (isolatedShapes, danglingConnectors, totalIssues), `issues[]`
+
+---
+
+### Layout
+
+#### `page-recommendations`
+
+Computes the bounding box of all shapes and recommends the smallest standard landscape page size that fits with an 80 px margin (first page).
+
+Standard sizes: A4 (1169×827), A3 (1654×1169), A2 (2339×1654), A1 (3307×2339). Falls back to custom rounded size.
+
+**Output:** `currentPage` (width, height, orientation), `contentBbox`, `required` (min size needed), `recommendedPage` (name, width, height), `checks` (contentFitsCurrentPage, hasAdequateMargin, isLandscape)
+
+---
+
+## Supported file formats
+
+- Bare `<mxGraphModel>` XML files
+- `<mxfile><diagram>…</diagram></mxfile>` wrappers (draw.io desktop format, base64+deflate encoded, multi-page supported)