spb/countryatlas

API: /pulse, /movers, /extremes, /scatter, /trajectory, /finder, /peers, /indicators/{slug}/{related,distribution,frames,quality}, /rankings/{id}/race, /regions/compare, /countries/{id}/{story,quality}, dna?reference=, /updates, search intents (type action); shared per-snapshot cross-section cache; 13 API tests.
Pipeline: structural_break / trend_reversal / volatility_spike detectors, similarity contributions carry value_a/value_b, deterministic retry/backoff honouring Retry-After, validation rules schema_change / impossible_year / null_spike / vintage_shift, ≥90 % observation-count integrity guard, meta.source_health + previous_observation_count, build logs; group descriptions in the registry; docs updated. 138 tests pass.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

- docs/API.md: contract for the analytics endpoints (pulse, movers, extremes, scatter, trajectory, finder, peers, related, distribution, frames, race, regions/compare, story, quality, updates, search intents) and change-detection 2.0 kinds
- src/countryatlas/stats.py + tests: deterministic YoY/CAGR/rolling/trend/volatility, ranks/percentiles/z-scores, records, structural break, persistent reversal, Pearson/Spearman/OLS/Theil–Sen, quantile breaks, histogram, convergence
- web: direction-of-change tokens (inc/dec, diverging ramp, second sequential ramp), container/full-bleed/ticker/badge utilities, styled range input
- web: navigation 2.0 (Explore · Countries · Compare · Rankings · Indicators · Changes · More ▾; mobile Explore · Countries · Compare · Rank · Search), MainFrame full-bleed for explorers, routes for every new page, i18n split (core/flagship/platform), types-analytics.ts, useUrlState, YearSlider, IndicatorSelect/Segmented
- fix: compare preset label and member count were adjacent without a separator ("G7 7 countries" read as "G77 countries"); package.json mock-api script pointed at a missing file

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>