Lower computation expressions, sequences, quotations, and resumable code

Parent: #8
Blocked by: #35

Outcome

Implement the specialized F# translations that build on the core typed and lowered representations.

Acceptance criteria

• Computation-expression syntax translates through general builder lookup and typing, including binding, return, combination, delay, loops, exception handling, resource use, custom operations, and applicative forms.
• Sequence expressions and quotations preserve their specified semantic and metadata contracts.
• Resumable-code and task-like state-machine lowering covers suspension, resumption, cancellation, exception paths, disposal, generic builders, and debug anchors.
• Tests use multiple unrelated compiler-owned builders and state-machine programs; no production branch recognizes a library namespace, type, or member.
• Generated code passes runtime, downstream F# consumption, portable-PDB, and NativeAOT consumer checks within the declared envelope.
• Dynamic and optimized modes remain behaviorally compatible with the relevant compiler options.

Decision inputs

Issues #5, #6, and #18; ADRs 0006, 0008, 0015, and 0027.

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

Start with parent issue #8 and unblocker #35, then read issues #5, #6, and #18 plus ADRs 0006, 0008, 0015, and 0027. The work is complete when the listed computation-expression, sequence, quotation, and resumable-code behaviors pass compiler, runtime, downstream F# consumption, portable-PDB, NativeAOT, dynamic, and optimized-mode checks.