Plan lifecycle: ban em dashes and require durable solutions

[DocksDocks]

Closes #27

Implements the reviewed plan #27:

• grammar_cutover - the v3 record grammar is ASCII-hyphen only: ### Plan review - <date>, ### Code review round <n> - <date>, - finding separators, and - for empty Steps Depends and queue Depends on cells. Em-dash records are ineligible exactly like malformed records; the live queue sentinel is migrated.
• body_dash_ban - check refuses any U+2014 in a plan body (check 10 family, count stays 13); new refuses U+2014 in title and goal before gh issue create; status <n> blocked --reason refuses an em-dash reason before the composed-body write.
• durable_policy - one shared clause on every policy surface (manager drafting, reviewer lens, both shipped wrappers, both Codex TOMLs, codex templates, plan-contract.md, docs/PLAN.md, template): plans deliver durable root-cause solutions; a temporary fix requires an explicit user request recorded in the plan; reviewers treat an unrequested temporary fix as a finding.
• docs_grammar - zero U+2014 bytes remain in lifecycle-owned skills, references, wrappers, the authoring node, docs/PLAN.md, and both test suites; docs/PLAN.md stays byte-identical to the template fence; closed em-dash-era plans yield no trusted verdict (pinned by fixtures).

Reviews: plan review rounds 1-4 repair (AGENTS.md scope, record-standard policy surfaces, show/archive legacy behavior, createPlan and blocked-reason write paths, live queue sentinel), round 5 pass; code review round 1 pass with no findings. This plan's own body was migrated to the hyphen grammar mid-flight through the new validation.

Verification: scripts/tests/plan-cli.mjs, plan-skill-phases.mjs, plugin selftest, scripts/ci.mjs --plugin plan-lifecycle, and full scripts/ci.mjs all exit 0.