docs(discovery): adopt AI Catalog urn:air: identifier convention (ADR 0015) (#31)

## What & why

Adopts the AI Catalog **`urn:air:`** identifier-naming convention
standardized in
[Agent-Card/ai-catalog#36](https://github.com/Agent-Card/ai-catalog/pull/36)
(ADR 0015) for this extension's discovery docs.

This repo's only identifier-naming surface is the **MCP Catalog Entry**
in [`docs/discovery.md`](docs/discovery.md). It previously used a
repo-local `urn:mcp:server:<name>` URN. `docs/discovery.md` describes
the MCP Catalog as *"a minimal, MCP-scoped subset of the AI Catalog
specification"* whose entries *"can be used as-is within a full AI
Catalog document"* — a claim the old format contradicted, since the AI
Catalog now standardizes the domain-anchored
`urn:air:{publisher}:{namespace}:{name}` form.

### Changes (doc-only, `docs/discovery.md`)

- Replace the `urn:mcp:server:<name>` convention with the AI Catalog
`urn:air:` form.
- Document the segments for an MCP server:
- **`publisher`** — the publisher's domain (forward DNS), e.g.
`example.com`, matching ADR 0015's framing that the publisher is a
domain.
- **`namespace`** — optional, populated per the AI Catalog specification
(the examples omit it).
- **`name`** — the server-name suffix (the segment after the `/` in the
referenced Server Card's reverse-DNS `name`), e.g. `weather`.
- So a Server Card named `com.example/weather` can be referenced as
`urn:air:example.com:weather`.
- Update all 4 catalog examples accordingly.

### Design notes for reviewers

- **Forward-DNS publisher**, anchored on the publisher's domain per ADR
0015.
- **Server Card schema deliberately untouched.**
`schema.ts`/`schema.json` have **no `identifier`/`identity` field** —
the card carries `name` (reverse-DNS) only — so this is a discovery-doc
change, not a schema change. Keeps the PR minimal and avoids pre-empting
unresolved SEP-2127 discussion.
- **Related open question:** issue #26 ("Remove the MCP Catalog") — this
aligns the identifier format while the MCP Catalog exists and does not
pre-empt that discussion.

## Verification

- [x] **Self-review (fresh-eyes) done.** Ran independent in-process
reviews of the diff across iterations; findings (an
incorrectly-attributed `urn:air:local:` form; reverse- vs forward-DNS
publisher) were addressed.
- [x] **ADR 0015 cross-checked against source** — verified the
`urn:air:{publisher}:{namespace}:{name}` form, the forward-domain
example `urn:air:example.com:...`, and the optional namespace against
the raw `adr/0015-agent-identifier-naming.md` in PR #36.
- [x] **All 4 examples internally consistent** with the documented
mapping; example `url` hosts match the publisher domains.
- [x] **No stale references** — `grep` confirms zero remaining
`urn:mcp:server:` occurrences.
- [x] **Schema untouched & in sync** — `npm run check` → `✓ schema.json
is up to date`; `tsc --noEmit` passes.
- [x] **Examples validate** — `npm run validate` → `All 7 example(s)
passed.`
- [x] **Formatting** — `npm run format:check` (prettier) passes on all
tracked files.
- [x] **CI green** — confirmed on the pushed branch (`build`, `CodeQL`,
`Analyze` all pass).

Local proof:

```
$ npm run check
✓ schema.json is up to date     (+ tsc --noEmit, no errors)

$ npm run validate
All 7 example(s) passed.

$ npm run format:check
All matched files use Prettier code style!
```

Documentation-only change; no UI and no runtime/logic behavior to
exercise beyond the schema toolchain above.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: tadasant <bob@tadasant.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

docs/discovery.md

@@ -52,13 +52,31 @@ Each entry in the `entries` array describes a single MCP server and MUST contain
 
 | Member        | Type   | Required | Description                                                                           |
 | :------------ | :----- | :------- | :------------------------------------------------------------------------------------ |
-| `identifier`  | string | Yes      | A URN identifying this server (e.g., `urn:mcp:server:com.example/weather`)            |
+| `identifier`  | string | Yes      | A logical discovery URN for this server (e.g., `urn:air:example.com:weather`)         |
 | `displayName` | string | Yes      | A human-readable name for the server                                                  |
 | `mediaType`   | string | Yes      | The media type of the referenced artifact. MUST be `application/mcp-server-card+json` |
 | `url`         | string | Yes      | URL where the full [Server Card](#mcp-server-cards) can be retrieved                  |
 
-The `identifier` MUST begin with `urn:mcp:server:` and end with the `name` value of the
-referenced Server Card, with no characters in between.
+The `identifier` is a **logical discovery name** that follows the
+[AI Catalog](https://github.com/Agent-Card/ai-catalog) domain-anchored URN convention
+standardized in [ADR 0015](https://github.com/Agent-Card/ai-catalog/pull/36):
+
+```
+urn:air:{publisher}:{namespace}:{name}
+```
+
+The segments are:
+
+- **`publisher`** — the publisher's domain (forward DNS), e.g. `example.com`. ADR 0015
+  anchors the identifier on this domain.
+- **`namespace`** — optional, populate if you wish in accordance with the AI Catalog specification
+- **`name`** — the server's name suffix, i.e. the segment after the `/` in the referenced Server
+  Card's reverse-DNS `name`, e.g. `weather`.
+
+So a Server Card named `com.example/weather`, can be referenced as
+`urn:air:example.com:weather`. Anchoring the identifier on the publisher's domain keeps
+it globally unique and stable across infrastructure changes, and lets an MCP Catalog entry
+be indexed as-is within a full AI Catalog document.
 
 ### Example: Single Server
 
@@ -69,7 +87,7 @@ A domain hosting a single MCP server, using only the required fields:
   "specVersion": "draft",
   "entries": [
     {
-      "identifier": "urn:mcp:server:com.example/weather",
+      "identifier": "urn:air:example.com:weather",
       "displayName": "Weather Service",
       "mediaType": "application/mcp-server-card+json",
       "url": "https://example.com/mcp/server-card"
@@ -87,19 +105,19 @@ A domain hosting several MCP servers, each with its own server card:
   "specVersion": "draft",
   "entries": [
     {
-      "identifier": "urn:mcp:server:com.acme/code-review",
+      "identifier": "urn:air:acme.com:code-review",
       "displayName": "Code Review Assistant",
       "mediaType": "application/mcp-server-card+json",
       "url": "https://acme.com/code-review/server-card"
     },
     {
-      "identifier": "urn:mcp:server:com.acme/docs-search",
+      "identifier": "urn:air:acme.com:docs-search",
       "displayName": "Documentation Search",
       "mediaType": "application/mcp-server-card+json",
       "url": "https://acme.com/docs-search/server-card"
     },
     {
-      "identifier": "urn:mcp:server:com.acme/ci-cd",
+      "identifier": "urn:air:acme.com:ci-cd",
       "displayName": "CI/CD Pipeline",
       "mediaType": "application/mcp-server-card+json",
       "url": "https://acme.com/ci-cd/server-card"