feat(phase-10): deliver platform and Tier B convergence

[ZSeanYves]

Scope

Delivers Phase 10 PR-100 through PR-105 from docs/PROJECT_PLAN.md:

• real Native OS, architecture and TTY probes, Windows/Unix process and signal semantics
• confirm/--yes, chooser and editor workflows
• color, command style, time/timestamp and Unicode display width
• automatic source-aware Markdown loading and final ADR-0017 decision
• exhaustive CLI/settings/attributes/builtins and 2,417-test compatibility classification

Compatibility baseline: just 1.57.0 at e01a6bd7e7a30baf86bc86d2b95b0998ebbdc36f.

Target matrix

• Native: 300/300 tests; local macOS aarch64 real platform and interactive gate passed
• wasm1: 295/295 tests; portable platform/terminal fallback and Phase 10 package gates passed
• wasm-gc/js: strict moon check --target all --warn-list +73 passed
• Ubuntu/macOS/Windows: tools/check_phase10_platform.sh runs in every Native matrix job

Compatibility evidence

• 2,417/2,417 upstream registrations classified, zero planned
• 1,844 covered-by, 526 explicit unsupported, 35 completion exclusions, 12 not applicable
• Phase 10: 40 covered, four module-aware chooser differences, eight exclusions/not-applicable
• fixed upstream tangle suite: 5/5 passed unchanged
• exact inventories: 50 options, 19 commands, 29 settings, 29 attributes, 83 builtins
• all 39 upstream JUST_* argument bindings classified and enforced

Mandatory second audit

The first remote run, Actions run 31611054327, passed quality, Ubuntu, macOS and Windows. The required second implementation/document review then found and remediated the CLI environment entry-point gap:

• production now passes the HostEnv snapshot into argparse with argv > env > default precedence
• falsey boolean environment values no longer create phantom conflicts
• JUST_UNSTABLE matches upstream falsey/arbitrary-truthy behavior
• unsupported environment bindings fail explicitly when enabled
• JUST_JUSTFILE=- reads stdin, while explicit argv overrides it
• help/version remain immediate even with conflicting or unsupported environment values
• the manifest verifier exact-checks all 39 bindings and real platform gates cover JUST_YES and stdin loading

Safety, dependencies, and rollback

• no production dependency added
• Native platform FFI remains isolated to the host_native leaf
• Wasm inspect remains deny-write and deny-spawn
• cancellation uses bounded graceful process-group handling; script cleanup and output bounds remain enforced
• no persistent cache schema or policy expansion is introduced

Verification

• moon info && moon fmt
• ./tools/check.sh
• Native 300/300 and wasm1 295/295
• Phase 6-10 dedicated gates
• fixed upstream tangle oracle 5/5
• documentation, generated-map and manifest consistency checks

Phase 10 remains pending only until remediation CI, merge, protected-main CI, and final evidence recording complete.