docs(readme): professional + simple rewrite — best-for / not-for, one hero, refreshed stats

The previous README opened with ~100 lines of inline animated SVGs
(the Joy of Math demo wall) before a new reader could establish what
Glyph even is. Great wow factor, terrible "professional landing
experience." Plus five overlapping "where to go" sections —
Quickstart, Interactive docs, Documentation, Where to go next,
Examples — that diluted the navigation.

Reorganized for first-scroll clarity. New shape:

  1. ONE hero animated SVG (the sine-wave story).
  2. Four primary action links (playground, learn, Claude, discuss).
  3. "What Glyph is best for" — 6 explicit use cases.
  4. "What Glyph is NOT for" — 3 honest limitations.
  5. Three-path Get Started (agent / library / no-install).
  6. 9-tile demo grid compressed below the fold.
  7. Architecture diagram + 1-paragraph explanation.
  8. Documentation table (8 docs ranked by user intent).
  9. Comparison (tight 8-row, link to full 16-row).
  10. Packages, Status, Requirements, Community, License.

Length: 401 → 271 lines (-32%). One canonical link per concept;
the previous version pointed at the LEARN guide / playground /
docs/MATH.md / site/index.html / discussions from five different
sections, often with different anchor text.

Refreshed every stale stat in flight:
  - "v0.0.20 on main"      → v0.2.0
  - "679 tests passing"    → 819 tests passing
  - "11 mark types"        → 21 mark types
  - "8 audit rules"        → 11 audit rules
  - "8 demos in site/"     → 9 demos
  - "4 brand presets"      → now includes "playground" + "3b1b"
  - "5 animation kinds"    → confirmed
  - "0 telemetry"          → preserved

Added what was missing for "know what it's best for":
  - Explicit "best for" list (6 use cases — agent charts, CI
    visual regression, provenance-auditable analytics, self-
    explaining charts, kid-persona math, SQL-embedded analytics).
  - Explicit "NOT for" list — high-frequency WebGL dashboards,
    Plotly drop-in, print-quality typography. Honesty about
    where Glyph isn't the right tool.
  - Cryptographic provenance seal called out in the comparison
    table (new column since the previous version).
  - Updated architecture diagram to show provenance + Explanation
    + audit findings as emitted artifacts.

The Joy of Math demo wall (9 inline animated SVGs) is preserved
in the "See it in action" section — moved below the fold so the
top of the page reads as a professional library landing instead
of a marketing splash, but the demos are still there for readers
who scroll. Each tile gets a one-line caption that names the
feature responsible (multi-scene timeline, traveler mark, draw-in
animation, streamlines, Bezier construction, parametric curve,
annotation, two BrandKit presets).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: seanhanca