docs: BGP workload integration plan with ASAPPlanner

[zzylol]

This proposal replaces the original cross-repository plan with a fixed preprocessing boundary for the BGP MVP.

Decision

• A BGP preprocessor owns MRT decoding, schema normalization, AS-path parsing, derived columns, hop/edge fanout, and stateful transition/gap computation.
• The preprocessor publishes versioned relational tables such as bgp_updates_enriched, bgp_path_hops, bgp_path_edges, and bgp_route_events.
• ASAPPlanner parses normalized SQL over those physical columns and applies only generic query-shape, sharing, summary, lifecycle, and cost rules.
• ASAPPlanner does not parse BGP-specific string/array expressions and does not generate a transformation plan.
• ASAPQuery validates the generic plan and maintains/reads counters, sketches, sets, and exact aggregates over preprocessed streams.
• ClickHouse remains the exact oracle/fallback. ASAPCollector integration is not part of the MVP.

What the plan adds

• A component responsibility table and end-to-end Mermaid flowchart.
• A versioned preprocessing schema/data-quality contract.
• The normalized-query boundary, with accepted and intentionally unsupported SQL examples.
• Generic Planner/runtime capability requirements.
• Phased delivery from an exact shared-count slice through fanout tables, distinct/multi-aggregate support, preprocessed stateful events, and broader composition/costing.
• Separate preprocessor, Planner, and runtime validation gates.
• Explicit non-goals preventing BGP derivation from leaking back into Planner IR.

The existing SQL-shape design is retained as documentation of the prototype branch and a correctness reference; its tau derivation path is explicitly not the proposed Planner integration contract.

Validation

• git diff --check passed.
• Markdown code fences are balanced.
• Referenced local design documents exist.
• Documentation only; no runtime or benchmark claims are made.

Base: sql-normalizer-pattern-recognition.