refactor(docs/quick-tour): modernize hello-pinecone to pinecone 9.0

## Purpose

hello-pinecone.ipynb pinned pinecone==8.0.0 and had imports scattered
across non-first code cells (code cells 2, 5, 8, 10), failing
check-structure. Ruff reported I001 import-sorting errors in 3 cells.

## Solution

- pinecone==8.0.0 → pinecone==9.0.0 (cell 0, pip install)
- Consolidate all unconditional imports into the first code cell
  (pip install cell) per check-structure requirements
- Sort imports: stdlib (os, random, time) then third-party
  (pandas, pinecone) with blank line between groups
- Remove scattered import lines from cells 2, 5, 8, 10
- Use keyword arguments throughout (per .ai/notebook-standards.md:53)

Refs: harness task NB-087.

Author: jhamon