test: add CLI coverage for target capability facts

[gke0op]

Summary

Adds CLI test coverage for zero targets output, asserting:

• Host target has process/runtime capabilities (proc, fs, net)
• capabilityFacts include hosted process/runtime surface
• Unavailable capabilities appear with available: false
• Non-host targets (wasm32-wasi) don't have proc capability

Testing

• All 10 CLI tests pass (9 existing + 1 new)
• Docs tests pass

Closes #3

[vercel]

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[gke0op]

Also includes docs improvements:

• Add MutSpan to Memory And Ownership primitives table (docs: add MutSpan<T> to primitives type table #34)
• Add expected zero --version output to getting started (docs: add expected output and PATH persistence to install guide #33)
• Add PATH persistence note for shell profile (docs: add expected output and PATH persistence to install guide #33)

[gke0op]

Rebase complete ✅

Rebased onto latest origin/main (v0.1.2, post borrow-provenance + HTTP client merge). All conflicts resolved. Each branch now has a clean linear history on top of current main.

[gke0op]

Rebased onto latest origin/main (v0.1.2). All conflicts resolved. Clean linear history.