feat(cli): spar moves enumerate — design-space exploration (Track E commit 4/8)

[avrabe]

Summary

Track E commit 4 of 8 for the v0.8.0 migration oracle.

Adds spar moves enumerate --component X [--target-filter PREFIX] [--format {json,text}], the second user-facing surface of the migration oracle. Builds on commit 3 (spar moves verify, #166).

• Candidate-target set. When the component declares Spar_Migration::Allowed_Targets, those names are used. Otherwise every Processor / VirtualProcessor in the instance is a candidate. --target-filter is an optional case-insensitive substring narrower applied on top of either set.
• Per-candidate verification. Each candidate runs the same overlay + analysis pipeline as spar moves verify: build a single-move BindingOverlay, validate it (Frozen / Allowed_Targets), run the analysis suite, and produce a structured MoveCandidate (target, ok, violations, diagnostics_count, slack_ns).
• Slack ranking (v0.8.0 simple metric). min(deadline − response_time) in picoseconds, parsed from RTA's info-level "thread '...' on processor '...': response time X <= deadline Y" diagnostics. None when RTA produced no usable info diagnostics; negative-sentinel when RTA reports a deadline miss. The full multi-objective ranking (weight, power, EMV2 cost) lands in commits 5-6.
• Output. JSON is the canonical machine-readable shape (consumed by the v0.9.0 MCP spar.enumerate_moves tool surface). Text is a sortable table with a total=N valid=K summary footer.
• Exit codes. 0 if at least one admissible candidate (valid >= 1); 1 otherwise (or input-resolution error).

What's NOT in this commit

• Full solver-driven enumeration (commits 5-6 — spar-solver integration).
• Multi-objective ranking (weight / power / EMV2 cost) — commits 5-6.
• MCP tool surface for spar.enumerate_moves — v0.9.0.
• Overlay-aware analysis passes (RTA / latency / bandwidth / EMV2 / ARINC653) — orthogonal Track E lift; current behaviour matches commit 3 (analyses see the un-overlayed instance).

Files changed

• crates/spar-cli/src/moves.rs — extends with EnumerateArgs, MoveCandidate, MoveEnumerateReport, run_enumerate, candidate-target derivation, slack parser, text + JSON renderers, and dispatch wiring (~640 LOC). Reuses VerifyArgs / Violation / build_report / resolve_component / fqn from commit 3.
• crates/spar-cli/src/main.rs — top-level help line for the new subcommand.
• crates/spar-cli/tests/moves_enumerate.rs — 10 new integration tests.
• crates/spar-hir-def/src/overlay.rs + lib.rs — read_allowed_targets now pub (re-exported) so enumerate can derive the candidate set without staging an overlay just to ask.
• artifacts/requirements.yaml — REQ-MIGRATION-006.
• artifacts/verification.yaml — TEST-MOVES-ENUMERATE linked to REQ-MIGRATION-{004,005,006}.

Test plan

• cargo build --workspace clean
• cargo test --workspace green (10 new integration tests + 4 new unit tests, additive on top of existing 800+; full workspace also passes)
• cargo clippy --workspace --all-targets -- -D warnings clean
• cargo fmt --all -- --check clean
• rivet validate clean (pre-existing INFO-level field-shape notes only)
• Frozen-component fixture: every candidate ok=false; valid=0; exit 1
• Allowed_Targets fixture: cpu3 (not allowed) excluded from candidate list
• RTA-fail fixture: every candidate has diagnostics_count > 0 and ok=false
• Target-filter narrows 3-CPU model to 2 candidates by substring match
• Text format ends with total=N valid=K
• JSON output deserializes into the documented schema
• Unknown component name yields non-zero exit and stderr mention
• spar analyze output is byte-identical before / after enumerate (overlay is read-only)

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 76.48725% with 83 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/spar-cli/src/moves.rs	76.63%	82 Missing ⚠️
crates/spar-cli/src/main.rs	0.00%	1 Missing ⚠️

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