docs: update website copy — sessions lasting days, crystal-clear memory

[BYK]

Summary

Updates the landing page copy to reflect the mega-session benchmark results and stronger value proposition.

Changes

Hero section

• Description: emphasizes "crystal-clear memory across sessions lasting days, hundreds of turns, any LLM provider"
• Chip: "400K+ Token Sessions" → "Sessions Lasting Days"

Stats strip

Already updated in #440: +70% vs compaction, 13/20 perfect scores, 2.3M+ tokens tested.

"The Problem" section

• Compaction step: now cites the real 2.3M-token benchmark — "compaction reduces 2.3 million tokens to an 11K summary, scoring 2.4/5. Lore scores 4.0/5."

"The Solution" section

• Recall step: "13 out of 20 perfect recall scores where compaction managed 5"

Feature cards

• Cost card: "Infinite sessions, lower cost" → "Sessions as long as you want" — "Work for days, hundreds of turns, millions of tokens — memory stays sharp."
• Compatibility card: "Works with any provider" → "Portable memory, any provider" — "Switch providers, switch tools, switch machines — your memory travels with you."

Ticker

• Lead with "2.3M tokens, 5 days, crystal-clear recall" + scores
• Added "Any provider, any tool — Portable memory that travels with you"
• Replaced "Compaction destroys details" (negative) with real benchmark numbers (positive proof)