Implement ordered symbols, scopes, signatures, and name resolution

Parent: #8
Blocked by: #29 and #30

Outcome

Resolve source and imported names across ordered F# files using stable compiler-owned symbols.

Acceptance criteria

• Namespaces, modules, opens, aliases, auto-open behavior, types, values, constructors, members, operators, active patterns, and attributes participate in the correct scopes.
• Earlier files and declarations are visible where allowed; later inputs never leak backward across F# source-order checkpoints.
• Shadowing, ambiguity, recursive scopes, accessibility, signatures, and implementation/signature matching follow focused Compatibility Oracle cases.
• Each resolved declaration and reference has a stable semantic identity independent of physical root and final metadata row order.
• Resolution records explicit dependency edges needed by diagnostics and incremental invalidation.
• Missing, inaccessible, or ambiguous names produce structured, ordered diagnostics without source-specific branches.

Decision inputs

Issues #2 and #19; ADRs 0004, 0014, and 0018.

This issue inherits the corpus-neutral acceptance policy in #8.

Start by reading parent issue #8 and the blockers #29 and #30, then review issues #2 and #19 plus ADRs 0004, 0014, and 0018. Use the focused Compatibility Oracle cases to define completion: source-order resolution, stable identities, dependency edges, and structured diagnostics must satisfy all listed acceptance criteria.