feat: migrate implement/spike/land workers to the clodex gateway route (one worker species)

[SSFSKIM]

Migrates the board pipeline's implement, spike, and land workers from the detached codex-CLI daemon species to the one-harness model the review loop adopted on 2026-07-15: every worker is a Claude-harness daemon spawned by daemon-spawn.sh, and the engine label (engine:codex/engine:claude, default codex) selects only the model route — clodex gateway settings (GPT models via the local proxy) or plain Claude models. This was the deferred scope recorded in the 2026-07-15 orchestrator-rebuild ExecPlan (Decision Log entry six), unblocked by the gateway review workers' sound dog-food behavior on ida-solution PR obra#570.

ExecPlan (authored from the 2026-07-17 human-approved grill, executed autonomously): docs/doperpowers/execplans/2026-07-17-implement-worker-clodex-migration.md.

What changed

• skills/implementing-tickets/references/engine-blocks/: the two per-engine execution blocks collapse into one execution.md (the split existed only because the codex CLI had no Skill tool; a gateway worker resolves plugin skills natively). The .agents/skills vendored-doctrine pointer goes with it.
• skills/issue-tracker/SKILL.md dispatch ritual steps 2–3: one spawn command for both routes; the codex route prefixes DAEMON_CLAUDE_SETTINGS/DAEMON_CLAUDE_EFFORT and pins model fable; codex-spawn.sh is dereferenced.
• skills/orchestrating-daemons/SKILL.md: board pipeline declared one-harness; codex-CLI scripts marked LEGACY (kept, byte-identical, for existing bound sessions).
• skills/orchestrating-daemons/scripts/daemon-finalize.sh: second lying-shape normalization — an ended session lingering state=blocked/status=idle finalizes idle (reply recorded through the blocked renderer so a pending question still surfaces). Found live: without it, every gateway implement worker's park→answer relay dead-ends.
• skills/reviewing-prs/scripts/land-dispatch.sh: the land worker was a second, undocumented codex-spawn consumer — migrated to the same gateway route, and its dedupe now finalizes a lingering claude-species lander before believing its meta (the codex exit review's single P1: a finished dry-run lander would otherwise block every later live dispatch forever).
• Living-spec revision notes on 2026-07-10-codex-workers-design.md and 2026-07-09-implement-worker-autonomy-design.md.

Validation evidence

• Hermetic: all suites green — test-protocol-content.sh (single-block + ritual assertions, RED shown before each change), test-daemon-scripts.sh (new blocked/idle finalize fixtures), test-codex-scripts.sh (unchanged, still green — legacy machinery untouched), test-land-dispatch.sh (gateway-env spawn + finalize-before-dedupe, RED first), test-review-dispatch.sh, test-board-scripts.sh, codex-plugin sync regression; repo shell lint clean; git diff --check clean.
• Live shakedown (scratch board, full protocol lifecycle): gateway worker spawned via the new ritual; registry meta persisted settings/effort/model=fable; first board write was the gate verdict (needs-human park on a deliberately unsettled taste fork, with recommended answer); board-answer.sh resume stayed on the gateway — the resumed worker's in-session probe echo "${ANTHROPIC_BASE_URL:-unset}" → http://localhost:8317, recorded verbatim in the PR it opened; [gate] re-pass — codex/direct; closing PR with Closes #N and TDD red→green evidence.
• Exit reviews: codex exec review --base main from a disposable clone (1 finding, the land-dedupe P1, fixed test-first) and an independent fresh-context reviewer over the final branch (Ready, no findings; verified every byte-identical constraint).

Out of scope (deliberate)

Full deletion of legacy codex machinery (separate follow-up once no bound codex session exists); the implementing-tickets skill-as-protocol restructure (work item 2 of the roadmap, next ExecPlan); the release carrying this to consumers.

Authored and executed by Claude Fable 5 (claude-fable-5) on Claude Code with the doperpowers plugin, from a human-approved brainstorming grill; the human partner reviews this PR.