Migration guides: from Postman, Bruno, Hurl, httpyac and curl/Taskfile #73

Why

docs/comparison.md says how apic differs from each tool; nothing says how to move from one. Someone arriving with a Postman collection or a Hurl suite wants a concept-mapping table, the command that does the bulk of it, and an honest list of what will not carry over.

What

A "Migrate" group under Guides in mkdocs.yml with one page per source:

• From Postman: collections → files and requests, environments → http-client.env.json, pm.* scripts → # @assert and # @capture or a shell loop, auth helpers → # @auth, apic import collection.json (Import Postman collections (v2.1) and environments #47), a worked example on the Postman Echo collection.
• From Bruno: .bru blocks → .http sections, vars:pre-request → env files, assert blocks → # @assert, scripts → not supported, bru run → apic run, reporters → --format.
• From Hurl: entries → requests, [Captures]/[Asserts] → directives, jsonpath → body.$, retry → # @retry, --variables-file → env files, --report-junit → --format junit.
• From httpyac: same files mostly work; what to change (@ref supported, scripts stripped, @import/@loop not), env file compatibility, running both side by side.
• From curl and Taskfile: apic import --curl (Import a curl command into a .http file #48) per command, keeping task as the front door (docs/taskfile.md), apic curl to get back.

Each page ends with a checklist and links to the relevant reference sections.

Where

docs/migrate/postman.md, bruno.md, hurl.md, httpyac.md, curl.md; mkdocs.yml; docs/comparison.md links to them.

Depends on

• Import Postman collections (v2.1) and environments #47 (Postman import) and Import a curl command into a .http file #48 (curl import) for the commands; the pages can land first with the manual mapping and gain the command when it ships.

Tests

Docs build, link check, and a learn-style runnable block per page where a command exists.