docs: migrate project memory governance

.project-docs/05-agent-entry/read-before-coding.md

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+# Read Before Coding
+
+Before editing code, verify that the implementation plan passed both the Concurrent Task Gate and Planning Gate. Confirm the task ID, branch, worktree, owner, and active task record still match.
+
+If the plan is stale, ownership changed, or new peer scope affects the plan, return to `read-before-planning.md`. Keep every later file and Git operation rooted in the owned worktree.
+
+Read the source files directly related to the target modules. Record feature progress, discovered constraints, verification, and promotion candidates in `.project-docs/30-worklog/tasks/{task_id}.md`; leave canonical project memory to Integration Gate.