refactor(engineering-manager): extract implementation orchestration into a canonical skill

[IgorWnek]

Summary

This PR refactors the lower-tier implementation orchestration flow so the GPT-5.4 mini orchestrator can execute it more reliably.

The main change is moving the canonical implementation workflow out of tsh-engineering-manager.agent.md and tsh-implement.prompt.md into a single non-user-invocable skill: tsh-orchestrating-implementation.

As a result:

• tsh-engineering-manager becomes the WHO-only orchestrator
• /tsh-implement becomes a thin trigger
• workflow mechanics live in one canonical place
• branch conditions and quality gates are made more operational for lower-tier execution

Behavior preservation

This refactor preserves the existing implementation-orchestration workflow branches and keeps the downstream specialist-agent routing model intact.

The only intentional behavior change is:

• any Figma/UI-verification involvement is now a hard exclusion from Quick Flow and always routes to Full Flow

Why

• removes duplicated orchestration logic across the agent and prompt
• gives the workflow a single canonical owner
• makes flow selection and branch conditions more explicit and measurable
• improves reliability for the lower-tier orchestrator without changing the underlying workflow scope

Architecture overview

flowchart LR
    U[User / task input] --> P["tsh-implement.prompt.md\nthin trigger<br>GPT-5.4 mini"]
    P --> A["tsh-engineering-manager.agent.md\nWHO / persona / delegation roster / tool rules<br>GPT-5.4 mini"]
    A --> S["tsh-orchestrating-implementation\nSKILL.md<br>canonical workflow<br>Step 0 / Quick Flow / Full Flow<br>todo protocol / execution-plan step / quality gates"]
    S --> I1["Internal prompts<br>9 specialist agents + 12 routed prompts"]
    I1 --> I2["tsh-architect<br>`tsh-plan-reviewer`<br>`tsh-context-engineer`<br>`tsh-software-engineer`<br>`tsh-devops-engineer`<br>`tsh-code-reviewer`<br>`tsh-e2e-engineer`<br>`tsh-ui-reviewer`<br>`tsh-prompt-engineer`"]

Loading

[IgorWnek]

Everything up to date, added changelog entries, ready for review.