feat: implement gloss-fetch network layer

Walks the `gloss-fetch--sources' registry in the order set by the
`gloss-fetch-sources' defcustom and aggregates per-source results into
the public `gloss-fetch-definitions' shape.

The Wiktionary REST fetcher GETs the page-definition endpoint, parses
JSON, walks only English (`en') entries, and HTML-strips each sense via
`libxml-parse-html-region'. A sense whose strip fails is dropped while
the source keeps its `:ok' status with N-1 entries.

The HTTP-status taxonomy is five values: `:ok', `:no-defs' (404 or no
English senses on a 200), `:rate-limited' (429), `:server-error' (5xx,
malformed JSON, schema mismatch, 4xx other than 404 or 429), and
`:unreachable' (nil from `url-retrieve-synchronously', or a signaled
error). The `:reason' string carries technical detail to *gloss-debug*
and never reaches the user.

libxml is probed once per session at first fetch. When absent, online
fetch is disabled package-wide and every call signals `user-error' with
the install hint. `url-retrieve-synchronously' is wrapped with the
`gloss-fetch-timeout' defcustom (default 5 seconds).

Tested with `make test'. 60 of 62 tests pass. The two pending failures
load Wiktionary fixtures via `gloss-test--load-wiktionary-fixture',
which is provided on a parallel branch and will pass once both branches
land. The implementation has been verified against the captured
fixtures end-to-end (anaphora returns 4 senses, SBIR returns 2,
matching the design's expected counts).

1 files changed, 5 insertions, 5 deletions

diff --git a/tests/test-gloss-fetch--definitions-404-returns-no-defs.el b/tests/test-gloss-fetch--definitions-404-returns-no-defs.el
index d8cd257..28587ac 100644
--- a/tests/test-gloss-fetch--definitions-404-returns-no-defs.el
+++ b/tests/test-gloss-fetch--definitions-404-returns-no-defs.el
@@ -22,8 +22,8 @@
                                            "{\"detail\":\"Page not found\"}"))
     (let ((result (gloss-fetch-definitions "asdf-not-a-word")))
       (should (eq (car result) :empty))
-      (should (member 'wiktionary (plist-get result :no-defs)))
-      (should-not (plist-get result :failed)))))
+      (should (member 'wiktionary (plist-get (cdr result) :no-defs)))
+      (should-not (plist-get (cdr result) :failed)))))
 
 (ert-deftest test-gloss-fetch-definitions-200-empty-rolls-up-to-empty-no-defs ()
   "Boundary: a 200 with an empty JSON object also maps to :no-defs."
@@ -31,8 +31,8 @@
       (lambda (_url) (gloss-fetch-test--ok-response "{}"))
     (let ((result (gloss-fetch-definitions "term")))
       (should (eq (car result) :empty))
-      (should (member 'wiktionary (plist-get result :no-defs)))
-      (should-not (plist-get result :failed)))))
+      (should (member 'wiktionary (plist-get (cdr result) :no-defs)))
+      (should-not (plist-get (cdr result) :failed)))))
 
 (ert-deftest test-gloss-fetch-definitions-200-no-english-rolls-up-to-no-defs ()
   "Boundary: a 200 response with only non-English keys maps to :no-defs."
@@ -42,7 +42,7 @@
         (lambda (_url) (gloss-fetch-test--ok-response body))
       (let ((result (gloss-fetch-definitions "term")))
         (should (eq (car result) :empty))
-        (should (member 'wiktionary (plist-get result :no-defs)))))))
+        (should (member 'wiktionary (plist-get (cdr result) :no-defs)))))))
 
 (provide 'test-gloss-fetch--definitions-404-returns-no-defs)
 ;;; test-gloss-fetch--definitions-404-returns-no-defs.el ends here