feat/integration log references

[blaggacao]

• feat: link ecommerce integration log with payment session log
• feat: add reference doc to ecommerce integration log

Context

• Frappe may act as "custom payment method"
• The special checkout page captures the order data
• Then it either or issues (background) synchronization
• It then redirects to the payment session
• The EIL becomes the central integration document for in-flight orders
  • Therefore the payment status and PSL is replicated onto it to quickly assess the overall status of such checkout
• The payment session runs a success hook on its refdoc (= the EIL)
  • Therefore hold a reference to the refdoc of the EIL
  • This allows charge success hooks to affect the business flow of the actual target refdoc (i.e. Sales Order), assuming that the synchronization had been successful and that it had written back the reference of the target doc onto the EIL

This is used by a WIP Ecwid integration, but which is not yet quite ready to PR.

[blaggacao]

Go for it now. The future is promised to no one. - Wayne Dyer

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

Fears are nothing more than a state of mind. - Napoleon Hill

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

What the caterpillar calls the end of the world, the master calls a butterfly. - Richard Bach

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

Watch your thoughts, they become your words Watch your words, they become your actions Watch your actions, they become your habits Watch your habits, they become your character Watch your character, it becomes your destiny. -

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

You may say Im a dreamer, but Im not the only one, I hope someday you will join us, and the world will live as one. - John Lennon

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

I have just three things to teach: simplicity, patience, compassion. These three are your greatest treasures. - Lao Tzu

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

The important thing is this: to be able at any moment to sacrifice what we are for what we could become. - Charles Dubois

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

Obstacles are those frightful things you see when you take your eyes off your goal. - Henry Ford

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

Our distrust is very expensive. - Ralph Emerson

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}

[blaggacao]

An invincible determination can accomplish almost anything and in this lies the great distinction between great men and little men. - Thomas Fuller

---

_{Kindly help move this PR forward. Many thanks from Yours Sincerely!}