Upgrade & unify Pinecone SDK across apps (namespace-notes/server v2, python pinecone-client, next-auth beta)

[jhamon]

Theme: Dependency Hygiene (primary SDK)

Problem

Pinecone SDK versions are inconsistent and stale across the four apps, and there is a beta pin:

App	Manifest	Pinecone dep	Status
legal-semantic-search	package.json	@pinecone-database/pinecone ^4.1.0	behind current stable
namespace-notes/server	package.json	@pinecone-database/pinecone ^2.1.0	two+ majors behind
shop-the-look	requirements.txt	pinecone-client==4.1.0	deprecated package name (renamed to pinecone) + behind
namespace-notes/client	package.json	next-auth 5.0.0-beta.31	beta pre-release pin

namespace-notes/server on JS SDK v2 is the biggest gap; the Python app still uses the deprecated pinecone-client distribution (the maintained package is pinecone). These should be brought onto the current stable SDK and unified where practical.

Proposed fix

• Verify the current stable versions first (npm @pinecone-database/pinecone; PyPI pinecone) rather than assuming a number — use the Pinecone docs skills for the current API surface.
• Upgrade @pinecone-database/pinecone in namespace-notes/server (v2 → current) and legal-semantic-search (v4 → current), adjusting call sites to the new API surface (init/client construction, index handles, query/upsert shapes). Bump @langchain/pinecone accordingly in legal-semantic-search.
• Migrate shop-the-look from pinecone-client to the pinecone package on current stable and update Python call sites.
• Unpin next-auth from 5.0.0-beta.31 to a stable release (or document explicitly why the beta is required).
• One library at a time, running the CI safety net after each.

Acceptance criteria

• Every app on the current stable Pinecone SDK; shop-the-look off the deprecated pinecone-client; no accidental beta pins (or a documented justification).
• Each app builds and its Pinecone flows work after migration; README snippets updated to match (see parent Docs checkbox).

Blast radius

risky — API-surface changes across multiple majors touch core query/upsert logic in three apps.

Dependencies

Depends on #71 (CI safety net) — do not attempt before CI exists. Coordinate with #73 (lockfile regeneration).