Align POS API and web component contracts

[richard-gajda]

Changes

• Consolidate the POS API JSDoc corrections from the closed docs(pos): source-grounded Cart API JSDoc corrections (audit proposal) #4696–docs(pos): remove duplicate Window declaration in navigation-api (audit proposal) #4700 slices into this open draft so reference generation has maintained source inputs.
• Correct method/version-specific Cart outcomes, RPC Storage error handling, startup session/connectivity/locale state, GraphQL rejection handling, modal target pairing, camera guards, and hardware acknowledgement/printing limitations.
• Regenerate the complete POS component declaration set, not only components.d.ts. Public pos.* target imports now receive the inherited DOM/Preact declarations and nullable picker callback types.
• Keep canonical public documentation records (including TabList) while removing duplicate public markers on rolled JSX aliases. Preserve private reachable helper types.
• Update the existing patch changeset. No runtime implementation or package release is included.

Verification

• SDK build, type-check, and lint passed.
• A public pos.home.modal.render consumer accepts null for all four callbacks on each of five picker families, rejects a numeric callback, and resolves inherited Embed.src and TabList JSX types.
• Four Action caller/modal examples type-check against their actual public target APIs using CLI-style declarations.
• The actual docs generator built from generate-docs #461 at 87a1d05de8bdaaf76e80f0766056f274dcaef273 preserves nullable Product Search results and picker events. This is a local unreleased binding, not the SDK lockfile's published 1.2.2 dependency.
• SDK test discovery found no related tests; no suite pass is claimed. Native device/hardware behavior was source-reviewed, not device-tested.

Keep this PR in draft. No merge or package publication.