v2.6.2 — smarter schema guidance

Models querying GA4 through this server now get fixed automatically where possible: common metric/dimension name mistakes are aliased ('users' → 'totalUsers', 'sessionDefaultChannelGrouping' → 'sessionDefaultChannelGroup', and more), malformed filter structures are repaired transparently (bare filters, snake_case group names), and the tool documentation carries a data-driven 'common mistakes' section. Adds an optional query-intent category (fixed vocabulary, model-declared — never user text) and MCP protocol/capability awareness. No setup changes. Opt-out unchanged: DISABLE_TELEMETRY=1 or DO_NOT_TRACK=1.