Git-aware CLI flows already existed, but branch detection depended on
status-line parsing and /diff hid local policy inside a path exclusion.
This change makes branch resolution and diff rendering rely on git-native
queries, adds staged+unstaged diff reporting, and threads git diff
snapshots into runtime project context so prompts see the same workspace
state users inspect from the CLI.
Constraint: No new dependencies for git integration work
Constraint: Slash-command help/behavior must stay aligned between shared metadata and CLI handlers
Rejected: Keep parsing the `## ...` status line only | brittle for detached HEAD and format drift
Rejected: Keep hard-coded `:(exclude).omx` filtering | redundant with git ignore rules and hides product policy in implementation
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Preserve git-native behavior for branch/diff reporting; do not reintroduce ad hoc ignore filtering without a product requirement
Tested: cargo fmt; cargo clippy --workspace --all-targets -- -D warnings; cargo test --workspace
Not-tested: Manual REPL /diff smoke test against a live interactive session
This improves Rust prompt-building by deduplicating repeated CLAUDE instruction content, surfacing clearer project-context metadata, and truncating oversized instruction payloads so local rules stay useful without overwhelming the runtime prompt.
The change preserves ancestor-chain discovery while making the rendered context more stable, compact, and readable for downstream compaction and CLI flows.
Constraint: Keep existing CLAUDE.md discovery semantics while reducing prompt bloat
Constraint: Avoid adding a new parser or changing user-authored instruction file formats
Rejected: Introduce a structured CLAUDE schema now | too large a shift for this parity slice
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: If richer instruction precedence is added later, keep duplicate suppression conservative so distinct local rules are not silently lost
Tested: cargo fmt; cargo clippy --all-targets --all-features -- -D warnings; cargo test -q
Not-tested: Live end-to-end behavior with very large real-world CLAUDE.md trees
