refactor(workflow): make execution plans authoritative

[blendsdk]

Closes #4.

Outcome

• Makes each plan's 99-execution-plan.md the sole mutable task-progress authority.
• Derives Ready, Executing, Done, and Blocked, resume position, progress, and RD delivery directly from plan Markdown.
• Supports one or multiple RD identifiers on the plan's > **Implements**: declaration.
• Removes graph readiness/transition calls from normal skills and preserves direct ambiguity, artifact, specification-first, verification, and finding checks.
• Adds a one-shot codeops_plan_migrate.py <codeops-dir> [--apply] command for existing nested projects.

Deletion evidence

• 77 files changed relative to current origin/main.
• 9,771 lines deleted and 830 added (net -8,941).
• Removed codeops_state.py, codeops_state_lib/, both traceability schemas, the traceability reference, state fixtures, and graph-specific conformance tests.
• Removed transition requests, semantic revisions, compare-and-swap updates, writer locks, recovery journals, and graph migration code with the deleted engine.

Remaining authorities

• RDs: agreed behavior and acceptance criteria.
• 00-index.md: RD-to-plan mapping.
• 99-execution-plan.md: [ ], [~], [x], and [!] task progress.
• Git: history and recovery.
• Roadmaps/status output: derived views only.

The retained scripts/codeops_plan.py is a read-only Markdown parser used for derived status. It has no writable state, transition API, revision, lock, journal, or migration behavior.

The migration command is a bounded one-shot converter, not a state platform. It previews by default, requires a clean Git tree for apply, infers mappings only from existing declarations, roadmap links, or a single-plan/single-RD feature, and blocks all writes when any mapping is ambiguous. It updates Markdown before deleting active or archived feature graphs.

Focused lifecycle and migration coverage

• one-plan-to-many-RD mapping and derived RD completion;
• first [~], otherwise first [ ], resume selection;
• four plan lifecycle states and visible blocked reasons;
• status operation without traceability.json;
• guard that normal workflow skills do not invoke the removed interface;
• migration preview, multi-RD roadmap inference, clean-tree apply, ambiguous all-or-nothing refusal, alphanumeric RD IDs, and archived features.

Verification

• Windows-native portable verification: 58 non-shell conformance tests, all 16 skill manifests, plugin validation, Markdown links, six embedded contract checks, compiler/financial/web parity scenarios, and Python compilation passed.
• The three baseline hook tests directly execute .sh files and are not runnable by native Windows CreateProcess; no WSL or Git Bash was used.
• Ubuntu CI runs the retained five-gate suite for every pushed revision.