Restore the research/ ignore rule dropped in #99; add the README map link (#101)

#99 replaced the `research/` .gitignore rule with a comment asserting the
directory 'stays gitignored' — and dropped the rule itself. Nothing was
ignored any more: 1,170 files became stageable by a plain `git add -A`,
including jsessionid_ and .corp hostname hits that are on the research
repo's scrub list (research-repo AGENTS.md §7).

Restore the rule and add the README orientation block linking the canonical
map, which #99 left out of the README (it covered ARCHITECTURE, .gitignore
and docs/vendor-api/README.md, but README.md still had zero references).

Also adds a local research/README.md declaring the mirror non-canonical.
Gitignored by design, so it is not part of this diff.

Verified: research/ ignored again (0 stageable), 323/323 tests pass
(identical to clean-main baseline), no .ts touched.

Co-authored-by: NovaLux12 <nova@luxmail.co.uk>

Author: NovaLux12

.gitignore

@@ -13,6 +13,12 @@ state.json
 # The local notes stay gitignored because they carry material that must not
 # be published (vendor API keys, internal hostnames, raw archive captures).
 # The published repo is the citable surface; source comments link into it.
+#
+# The rule below is load-bearing, not documentation. PR #99 replaced the
+# `research/` rule with the comment above and dropped the rule itself, which
+# left 1,170 files - including jsessionid_ and .corp hostname hits from the
+# scrub list - stageable by a plain `git add -A`. Restored here.
+research/
 
 # macOS Finder artifacts (also created by some Linux/Windows tools when
 # editing files on a shared filesystem). Not source.

README.md

@@ -10,6 +10,17 @@ Sends your Medtronic pump and CGM data to [Nightscout](http://www.nightscout.inf
 automatically, by logging into Medtronic's CareLink servers and
 uploading what it gets.
 
+> **Medtronic publishes no API documentation.** The surface this bridge talks to
+> is reverse-engineered, and the map of it lives in a separate, continuously
+> re-verified repo: **[NovaLux12/carelink-api-research](https://github.com/NovaLux12/carelink-api-research)**
+> — [start here](https://github.com/NovaLux12/carelink-api-research/blob/main/docs/00-summary-the-map.md).
+>
+> Every source comment that makes a claim about CareLink links into it, and
+> [`docs/vendor-api/README.md`](./docs/vendor-api/README.md) records which finding
+> each one rests on. **Go there first** when debugging a fetch failure, checking
+> whether a route still exists, or changing how this bridge talks to CareLink —
+> and report what you find there, where a drift sweep will notice it.
+
 > **How close is this to the official app?** The **data** path is the
 > same one the official CareLink app uses — the bridge takes its login
 > configuration from the same discovery document and posts to the same