[Provider] Gate checker-owned member relations by ttsc schema

[samchon]

Problem

The graph consumer accepts published schema 3 as a compatibility snapshot, but edge validation currently accepts schema-5-only checker facts: overrides and member-level implements. The warning simultaneously says those facts predate schema 3 and are absent.

Acceptance

• Schema 3 rejects overrides and member-level implements based on endpoint facts while retaining container heritage implements.
• Schema 5 accepts the checker-owned member relation forms.
• Add negative schema-3 and positive schema-5 controls.
• Keep the compatibility warning truthful.

Discovered during #96; implementation may land in PR #97.

[samchon]

Review Round 4 caught a schema-3 heritage endpoint omitted by the initial gate: TypeScript legally allows class Impl implements Contract when Contract is a type alias to an object type. Canonical schema 3 emits this as class -> type implements; it is container heritage, not the schema-5 member relation. Acceptance therefore includes class -> class/interface/type heritage while still rejecting method/property member endpoints and every schema-3 overrides edge.

[samchon]

Review Round 5 verified that schema 3 cannot honestly satisfy the complete-manifest invariant for ordinary dependency-using projects: its producer emitted external declaration facts but attested only workspace SourceFiles. Canonical ttsc fixed this in 4c5e11e by using TSProgram.SourceFiles. PR #97 should therefore require manifest-complete schema 5 instead of advertising general schema 3 compatibility; loosening strict validation would invent trust the producer never supplied.

[samchon]

PR #97 addresses this by a stronger decision than the written acceptance criteria.

Rather than accepting schema 3 while gating its checker-owned member relations (overrides, member-level implements) and retaining container heritage, the provider now refuses schema 3 wholesale: SUPPORTED_DUMP_SCHEMA_VERSIONS is narrowed to [5], a schema-3 dump is rejected before it can seed the graph ("dump is schema v3, this client reads v5"), and the client falls back honestly to LSP while still returning project declarations (test_ttscgraph_published_schema3_falls_back_honestly).

Rationale: a schema-3 manifest cannot prove its member relations, so partial trust re-introduces exactly the dishonest-authority risk the campaign forbids; refusing it is fail-closed and truthful.

This diverges from the literal AC (which keeps schema 3 working with gated relations), so I've left this issue open for your confirmation of the direction instead of auto-closing it. If you prefer the gate-and-retain behavior, say so and I'll restore schema-3 support with the endpoint-fact gate instead.