Exclude old/ compat tests from published @fedify/uri-template

The package previously shipped the `old/` directory and pointed
package consumers at `deno task test:old`, but those compatibility
tests only make sense inside the Fedify monorepo: they import from
`old/url-template.test.ts` and `old/uri-template-router.test.ts`,
and the `test:old` task lives in the workspace's *deno.json*, not
in the published artifact.

Drop the directory from both publish paths and rewrite the README
pointer so it directs readers to the source repository instead of
to a task they cannot run:

  -  `package.json` gains a `files` allowlist of `dist`, `package.json`,
     and `README.md`, mirroring the `@fedify/postgres` layout.
  -  `deno.json`'s `publish.exclude` adds `old/` alongside the other
     development-only directories.
  -  *README.md* replaces the `deno task test:old` snippet with a
     short note that the comparison tests live under
     *packages/uri-template/old/* in the source repository and are
     intentionally not part of the published package.

Reported by CodeRabbit in
#758 (2026-05-11).

Assisted-by: Claude Opus 4.7 (1M context)

Author: 2chanhaeng

packages/uri-template/README.md

@@ -114,14 +114,11 @@ The important differences are:
     active route entries directly, which keeps the implementation independent
     and dependency-free at runtime.
 
-The old implementation differences can be checked by running the compatibility
-tests in *old/url-template.test.ts* and *old/uri-template-router.test.ts*.
-These tests intentionally run Fedify's expected behavior against the old
-libraries, so the failing cases show the gaps:
-
-~~~~ bash
-deno task test:old
-~~~~
+The concrete differences from the previous [url-template] and
+[uri-template-router] libraries are encoded as compatibility tests under
+*packages/uri-template/old/* in the package's source repository.  Refer to
+those tests for behavior comparisons against the older libraries; they are
+not shipped in the published package.
 
 
 Features

packages/uri-template/deno.json

@@ -20,6 +20,7 @@
     "exclude": [
       "**/*.bench.ts",
       "**/*.test.ts",
+      "old/",
       "src/tests/",
       "summary.txt",
       "tsdown.config.ts"

packages/uri-template/package.json

@@ -45,6 +45,11 @@
     "test:bun": "bun test src/**/*.test.ts",
     "test": "node --experimental-transform-types --test src/**/*.test.ts"
   },
+  "files": [
+    "dist",
+    "package.json",
+    "README.md"
+  ],
   "keywords": [
     "Fedify",
     "URI Template",