tokmd-analysis-derived 1.9.0

Derived analytics computation used by tokmd analysis.
Documentation
# tokmd-analysis-derived

Derived metrics and tree output for analysis receipts.

## Problem
You need receipt-level rollups without pushing aggregation logic into the CLI or formatter.

## What it gives you
- `derive_report`
- `build_tree`
- `DerivedReport`, `DerivedTotals`, `ReadingTimeReport`

## Integration notes
- No feature flags.
- Consumes export data plus optional `window_tokens`.
- Produces totals, distributions, reading-time, COCOMO, TODO, and integrity data.

## Go deeper
- Tutorial: [Tutorial]../../docs/tutorial.md
- How-to: [Recipes]../../docs/recipes.md
- Reference: [Architecture]../../docs/architecture.md, [Root README]../../README.md
- Explanation: [Explanation]../../docs/explanation.md