Bring README, docs, and examples up to par

[nficano]

Post-refactor doc reconciliation.

Scope

• README reflects the current API surface and install path
• Quickstart actually runs end-to-end against the current build
• All examples compile/run and demonstrate idiomatic usage
• Inline doc comments accurate for any signatures changed in Refactor pass 1 #1/Refactor pass 2 — verification sweep #2
• Remove references to deprecated APIs or earlier design iterations

Blocked by

#2

Labels

documentation