Compact routine workspace capacity advisories

[chubes4]

Summary

• reserve emergency_triggered for blocking capacity thresholds
• project compact typed capacity status from routine workspace list/show abilities
• retain complete blocking evidence and direct advisory readers to workspace hygiene
• keep CLI envelopes compact while preserving explicit full evidence when available

Fixes #1307.

Verification

• php tests/worktree-disk-budget.php
• php tests/workspace-capacity-advisory.php
• php tests/workspace-command-startup-bounds.php
• php tests/workspace-list-cli-format-contract.php
• php tests/workspace-show-cli-format-contract.php
• PHP syntax checks for all modified source files
• git diff --check

AI assistance

• Model: openai/gpt-5.6-sol
• Tool: OpenCode
• Used for: Traced the contradictory capacity projection, implemented the shared ability-level compact contract, reconciled concurrent agent output, and ran focused verification.