docs: class to tags API doc

[LuLaValva]

New Doc: Tags API for Class API developers

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: c26e19f2-9af0-42ca-aa0a-ea1d589e5fbd

📥 Commits

Reviewing files that changed from the base of the PR and between 7f447e1 and c935661.

📒 Files selected for processing (1)

• docs/explanation/class-vs-tags-api.md

🚧 Files skipped from review as they are similar to previous changes (1)

• docs/explanation/class-vs-tags-api.md

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Walkthrough

Adds a new explanation doc at /docs/explanation/class-vs-tags-api comparing the Class API and Tags API, with sections on components, event handling, refs, lifecycle, derived values, examples, and further reading. Registers the new route in the generated typed routes and page module declarations, and adds a navigation entry to the app menu. Updates documentation guidance in .cursorrules and extends the language reference with a "Repeated Tag Vars" subsection describing iterable tag variables.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: adding documentation about transitioning from the Class API to the Tags API in Marko.
Description check	✅ Passed	The description is related to the changeset, clearly indicating a new documentation resource for Class API developers transitioning to the Tags API.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch class-to-tags-api

📝 Coding Plan

• Generate coding plan for human review comments

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[coderabbitai]

Actionable comments posted: 4

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@docs/explanation/class-vs-tags-api.md`:
- Line 131: Correct the typo in the sentence "In the Class API, running code
whens something mounts inside a loop requires a child component." by changing
"whens" to "when" so it reads "In the Class API, running code when something
mounts inside a loop requires a child component."
- Line 79: Fix the typo in the paragraph that recommends using element
references from tag variables (the sentence referencing getEl and
../reference/native-tag.md#element-references) by changing "usd" to "used" so
the sentence reads "...it can be used anywhere in the template."
- Around line 230-236: The example shows deriving num via the Marko const tag
but still renders input.num; update the output to use the derived value instead.
Replace the `${input.num}` render with the derived `num` (produced by
`<const/num=parseInt(input.num)>`) so the snippet demonstrates the derivation;
keep the Input interface and const declaration as-is and only change the output
expression to reference `num`.
- Line 1: The top-level heading "# Tags API for Class API Developers" is too
long; replace it with a concise 1–3 word H1 such as "# Tags API Guide" (or
simply "# Tags") by editing the heading line in
docs/explanation/class-vs-tags-api.md so the file starts with the shortened H1.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e75ceea0-dc44-4072-9218-0d2c659c5d6d

📥 Commits

Reviewing files that changed from the base of the PR and between f97b91e and 7f447e1.

📒 Files selected for processing (5)

• .cursorrules
• .marko-run/routes.d.ts
• docs/explanation/class-vs-tags-api.md
• docs/reference/language.md
• src/tags/app-menu/app-menu.marko