Add mobility content enrichment product lane

[mdheller]

Summary

Adds the first SynapseIQ Mobility Content and Enrichment lane as repo-backed doctrine, contract schema, semantic taxonomy, and synthetic package fixtures.

This PR establishes the line between reference substrate, observed content, derived enrichment, and sellable package output. It also encodes the privacy/permitted-use posture as contract and package mechanics rather than narrative only.

Added

• ADR-0002 for the mobility content and enrichment product lane.
• Mobility content/enrichment specification.
• JSON Schemas for:
  • Data Source Contract
  • Mobility Signal
  • Package Manifest
• Synthetic fixtures for:
  • footfall Data Source Contract
  • weekly POI footfall MobilitySignal
  • Retail Trade Area package manifest
  • EV / Logistics Corridor package manifest
• Semantic taxonomies for:
  • content lanes
  • package purposes
  • protected-location policy
  • confidence strategies

Product boundary

This is not a provider adapter tranche. It deliberately avoids hard-binding to Placer, StreetLight, Foursquare, PredictHQ, INRIX, HERE, TomTom, card networks, or any other vendor. Provider-specific work should happen only after contracts, privacy gates, package manifests, synthetic events, and evidence paths are stable.

Validation status

Connector-side compare confirms branch is ahead of main by 13 commits and adds 13 files. Local schema validation has not yet been run from a checkout.

Next tranche

• Add TypeScript schema loader/validator.
• Add synthetic raw footfall and vehicle/corridor payloads.
• Add normalizer interfaces and in-memory ADS-shaped event substrate.
• Add first deterministic package compiler for Retail Trade Area and EV / Logistics Corridor.