Scaffold Cargo workspace with ADR enforcement

[Brad-Edwards]

Summary

First capcom work order step (project scaffolding). Sets up the Cargo workspace, Rust toolchain, ADR enforcement, CI, and pre-commit hooks so subsequent work order steps have a building/testing/linting project to add code to. Mirrors aphelion's scaffolding pattern adapted for Rust.

What's in the PR

Cargo workspace (new):

• Cargo.toml — workspace manifest (resolver 2, edition 2024, Rust 1.85+, MIT, workspace lints)
• crates/capcom/ — library crate with placeholder version() and one passing unit test
• crates/capcom-engine/ — binary crate, entry point for the future co-located out-of-process engine node (ADR-012)
• rust-toolchain.toml — stable channel, rustfmt + clippy components, minimal profile
• rustfmt.toml — edition 2024

ADR enforcement (new):

• scripts/check-adr-conformance.sh — grep-based check for banned engines (ADR-001: MillenniumDB, Graphflow) and distributed primitives (ADR-003/005/009) over Rust source and Cargo.toml. Works in both pre-commit and CI modes with line-level // adr-override: ADR-NNN escapes.
• .claude/hooks/adr-boundary-check.sh — same checks as a Claude Code PreToolUse hook on Edit/Write.
• .claude/settings.json updated to register the new hook alongside protect_files.sh.

CI pipeline (replacing TODO placeholders in .github/workflows/ci.yml):

• adr-conformance job — runs the conformance script
• lint job — cargo fmt --all --check + cargo clippy --workspace --all-targets -- -D warnings
• test job — cargo build --workspace --all-targets + cargo test --workspace --all-targets
• All third-party actions pinned to commit SHAs.

Pre-commit additions to .pre-commit-config.yaml:

• Stage 3: cargo fmt --all --check
• Stage 4: scripts/check-adr-conformance.sh
• Clippy and full tests deliberately left out of pre-commit (too slow for fail-fast); CI handles them.

Docs / config:

• README.md — replaces "Project Name" placeholder with build/test/run commands, layout, and architectural constraints summary
• .gitignore — adds Rust entries (target/, *.pdb)
• .editorconfig — adds [*.rs] and [*.toml] sections
• CHANGELOG.md — new 0.2.0 entry

Also carried along (uncommitted working-tree state from the earlier Ground Control workflow migration):

• .ground-control.yaml — now populated with real cargo workflow commands (was commented-out placeholders)
• AGENTS.md, CLAUDE.md, .mcp.json — Ground Control Context pointers updated
• Deleted .claude/skills/{implement,ship,stage,review-tests,gh-workflow-monitor}/ — workflow skills now live at user level (~/.claude/skills/) per the skill centralization work tracked in Ground Control as GC-O008 / ADR-023
• Previous 0.1.0 CHANGELOG entry (Ground Control migration)

What's NOT in the PR

• No actual kernel code. lib.rs has only version(). main.rs prints a placeholder.
• No storage, data model, transactions, query execution, schema, or indexes. Those are the next work order step.
• No IPC / boundary contract implementation. Aphelion work order step 4.
• No local ADR document copies. capcom enforces aphelion's ADR numbers by pattern; it doesn't keep its own docs/adrs/ copies. Can be added later if wanted.

Verification (all pass locally)

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo build --workspace --all-targets
• cargo test --workspace --all-targets (1 test: capcom::tests::version_is_non_empty)
• scripts/check-adr-conformance.sh
• gc_get_repo_ground_control_context returns status: ok with full workflow block populated
• CI green on this PR

Test plan

• CI adr-conformance job passes
• CI lint job passes (fmt + clippy on the workspace)
• CI test job passes (build + test)