Fix README doc drift: typos, malformed support link, stale Beta banner

[jhamon]

Problem

README.md has several defects:

• Typos: "supprts", "supoorts" (appears 3x — SPLADE and SentenceTransformer 3.12 notes).
• Malformed contact link: [support](support@pinecone.io) renders as a broken relative link, not a mailto:.
• A prominent "public preview (Beta)" warning banner remains even though the package is at v0.11.0 and widely used — re-evaluate whether it is still accurate.
• Verify external doc links are still live (e.g. docs.pinecone.io/docs/hybrid-search).

Proposed fix & acceptance

• Correct the typos; fix the support link to mailto:support@pinecone.io; confirm/remove the stale Beta banner with maintainers; update any dead links.
• Acceptance: README renders cleanly, links resolve, wording matches current maturity.

Blast radius

safe (docs only).

Depends on

nothing