docs(migration): document individual memberships and email forwarder

[dealako]

Summary

Add current-state and migration write-ups for two flows being migrated from
myprofile + membership-ui into LFX Self Serve:

• Individual Memberships ($99/yr TLF Supporter): cross-app user journey,
  Stripe + Salesforce wiring, and gap analysis vs LFX Self Serve.
• Linux.com Email Forwarder ($150 lifetime alias): purchase + claim flow
  spanning myprofile, membership-ui, and the ITX mail-forwarder service, with
  UX unification as the primary migration win.

Also relax markdownlint MD013 to a 120-char limit (code/tables exempt),
disable MD060, and add a Migration section to the mkdocs nav.

Changes

 .markdownlint.json                          |  21 +-
 docs/migration/individual-memberships.md    | 631 ++++++++++++++++++++++++++++
 docs/migration/linux-com-email-forwarder.md | 475 +++++++++++++++++++++
 mkdocs.yaml                                 |   3 +
 4 files changed, 1125 insertions(+), 5 deletions(-)

Jira: LFXV2-1664

[coderabbitai]

Walkthrough

This PR adds two comprehensive migration documentation pages describing the current Individual Memberships and Linux.com Email Forwarder implementations with strategy and gaps for LFX One migration. It also updates markdownlint rules to enforce consistent line length and extends mkdocs navigation to surface the new Migration section.

Changes

Migration Documentation and Configuration

Layer / File(s)	Summary
Markdown linting rule updates .markdownlint.json	MD013 (line length) is enabled with 120-character limit excluding code blocks and tables; MD060 is explicitly disabled; several rules are reformatted into explicit multi-line objects.
Individual Memberships migration guide docs/migration/individual-memberships.md	End-to-end documentation of current Individual Memberships flow spanning myprofile entry points, membership-ui wizard, Stripe checkout, and member-service enrollment. Includes architecture diagrams, component/endpoint inventories, enrollment status derivation rules, configuration details, operational failure modes, migration patterns for LFX One, and API payload examples.
Linux.com Email Forwarder migration guide docs/migration/linux-com-email-forwarder.md	End-to-end documentation of current Linux.com Email Forwarder lifetime add-on covering purchase gating and alias management workflows across myprofile, membership-ui, and backend services (member-service, user-service, ITX). Includes architecture diagrams, component/endpoint inventories, membership-ui gating behavior, data-model derivation explaining independent sources of purchase and alias state, failure modes, and LFX One migration scope and open questions.
Documentation navigation mkdocs.yaml	New "Migration" section added to top-level navigation with links to Individual Memberships and Linux.com Email Forwarder migration guides.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding documentation for individual memberships and email forwarder migration flows.
Description check	✅ Passed	The description clearly explains the purpose of the changes, detailing the two migration flows, configuration adjustments, and navigation updates.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/LFXV2-1664-migration-docs

---

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[Copilot]

Pull request overview

Adds migration documentation for two legacy membership-related user journeys (Individual Supporter membership and Linux.com email forwarder add-on) and updates the documentation toolchain/navigation to support these new docs in LFX Self Serve.

Changes:

• Added two detailed migration/current-state write-ups under docs/migration/.
• Updated MkDocs navigation to include a new “Migration” section.
• Adjusted markdownlint configuration (MD013 to 120 chars with code/table exemptions; disabled MD060).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
.markdownlint.json	Updates Markdown linting rules/limits to better accommodate long-form migration docs.
mkdocs.yaml	Adds a “Migration” nav section pointing to the new docs.
docs/migration/individual-memberships.md	New documentation describing the current Individual Supporter membership flow and migration considerations.
docs/migration/linux-com-email-forwarder.md	New documentation describing the current Linux.com email forwarder add-on flow and migration considerations.

Comments suppressed due to low confidence (1)

docs/migration/individual-memberships.md:440

• Typo in the function name: Notifiy... should be spelled Notify... for readability/searchability (even in docs).

1. `NotifiyMembershipServiceError()` auto-files a **Jira ticket** and sends an SES email
   with subject "URGENT: Individual Enrollment" to support (`backend/modules/enrollment/index.js:416–456`).

---

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

docs/migration/linux-com-email-forwarder.md (1)

246-256: 🏗️ Heavy lift

Non-atomic rename operation is a significant operational risk.

The documentation correctly identifies that the alias rename is a four-step sequence with no rollback or transaction boundaries (lines 248-256). If steps 3 or 4 fail, the user loses their old alias without getting the new one. This is an excellent opportunity for improvement in the migration to LFX One—consider wrapping this in a saga pattern or compensating transaction to ensure atomicity.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@docs/migration/linux-com-email-forwarder.md` around lines 246 - 256, The
UpdateForwardAlias flow (enrollment.service.ts: UpdateForwardAlias) performs a
non-atomic 4-step rename using userService.UpdateUserEmails and
itxService.DeleteForward/CreateForward which can leave users without an alias if
steps 3 or 4 fail; fix by making the operation compensatable or atomic:
implement a saga/compensating transaction around UpdateForwardAlias that either
(a) creates the new ITX forward (itxService.CreateForward(newAlias, recipient))
and adds the new alias to the user (userService.UpdateUserEmails(token, add new
alias)) before removing the old forward and old alias, or (b) on any failure run
compensating steps to recreate the old forward and re-add the old alias (use
itxService.CreateForward with the oldAlias and
userService.UpdateUserEmails(token, add old alias)), add retry/backoff and
clear, well-scoped logging for each step, and surface errors so callers can
coordinate retries; update UpdateForwardAlias to orchestrate these compensations
and unit tests to cover failure points.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@docs/migration/linux-com-email-forwarder.md`:
- Around line 322-333: The docs note that member-service, ITX, and user-service
are independent and not automatically kept in sync, which is an operational
risk; update the migration plan to define a concrete consistency solution: add a
reconciliation job (e.g., a periodic reconciler service) that compares
member-service records for productID = 01t2M000005wBazQAE against ITX
alias/forward-to and user-service email lists and repairs or alerts on
mismatches, and/or define a saga/orchestration flow for purchase/alias changes
with compensating actions and robust error handling and logging; include clear
instructions in the document on how to run the reconciler, expected invariants,
and where to find logs/alerts.

---

Nitpick comments:
In `@docs/migration/linux-com-email-forwarder.md`:
- Around line 246-256: The UpdateForwardAlias flow (enrollment.service.ts:
UpdateForwardAlias) performs a non-atomic 4-step rename using
userService.UpdateUserEmails and itxService.DeleteForward/CreateForward which
can leave users without an alias if steps 3 or 4 fail; fix by making the
operation compensatable or atomic: implement a saga/compensating transaction
around UpdateForwardAlias that either (a) creates the new ITX forward
(itxService.CreateForward(newAlias, recipient)) and adds the new alias to the
user (userService.UpdateUserEmails(token, add new alias)) before removing the
old forward and old alias, or (b) on any failure run compensating steps to
recreate the old forward and re-add the old alias (use itxService.CreateForward
with the oldAlias and userService.UpdateUserEmails(token, add old alias)), add
retry/backoff and clear, well-scoped logging for each step, and surface errors
so callers can coordinate retries; update UpdateForwardAlias to orchestrate
these compensations and unit tests to cover failure points.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 115b792b-b15d-43d1-9409-4ee4961693d2

📥 Commits

Reviewing files that changed from the base of the PR and between 8f616cb and 21d3ccb.

📒 Files selected for processing (4)

• .markdownlint.json
• docs/migration/individual-memberships.md
• docs/migration/linux-com-email-forwarder.md
• mkdocs.yaml

[coderabbitai]

🛠️ Refactor suggestion | 🟠 Major | 🏗️ Heavy lift

Important consistency concern across three services.

The documentation explicitly states that member-service, ITX, and user-service are independent and "not automatically kept in sync — there is no saga or compensating transaction" (lines 332-333). This is a significant operational risk that should be addressed in the LFX One migration, potentially through eventual consistency patterns, saga orchestration, or at minimum better error handling and reconciliation tooling.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@docs/migration/linux-com-email-forwarder.md` around lines 322 - 333, The docs
note that member-service, ITX, and user-service are independent and not
automatically kept in sync, which is an operational risk; update the migration
plan to define a concrete consistency solution: add a reconciliation job (e.g.,
a periodic reconciler service) that compares member-service records for
productID = 01t2M000005wBazQAE against ITX alias/forward-to and user-service
email lists and repairs or alerts on mismatches, and/or define a
saga/orchestration flow for purchase/alias changes with compensating actions and
robust error handling and logging; include clear instructions in the document on
how to run the reconciler, expected invariants, and where to find logs/alerts.