fix(bug-tracker): follow the tracker to its v1 endpoint

lib/features/bug_tracker/data/bug_api.dart

@@ -3,6 +3,11 @@ library;
 
 import 'package:dpip/core/network/api_client.dart';
 
+/// The forum tag that marks a thread as about THIS app. A routing marker, not
+/// a category — it is filtered on, both by the server and again here, and
+/// never rendered.
+const String appBugTag = 'dpip';
+
 /// Reads the reported-bug threads from the tracker host.
 ///
 /// Absolute URL on purpose: `bamboo.exptech.dev` is a single host outside the
@@ -14,13 +19,18 @@ class BugApi {
 
   final ApiClient _client;
 
-  static const String _base = 'https://bamboo.exptech.dev/api/dc/bug';
+  static const String _base = 'https://bamboo.exptech.dev/api/v1/dc/bug';
 
   /// Every thread in the index, capped at 50 so the payload stays bounded as
   /// the tracker grows. The query rides the URL, so the ETag store keys it as
   /// its own resource.
+  ///
+  /// `tag` asks the server for this app's threads only. It matters for the cap
+  /// as much as for correctness: the tracker is shared with other products, so
+  /// an unfiltered page of 50 spends some of its rows on threads this app then
+  /// throws away — measured against the live index, 3 of 50.
   Future<dynamic> list() =>
-      _client.getAbsolute(_base, query: const {'limit': 50});
+      _client.getAbsolute(_base, query: const {'limit': 50, 'tag': appBugTag});
 
   /// One thread with its replies.
   Future<dynamic> thread(int id) => _client.getAbsolute('$_base/$id');

lib/features/bug_tracker/data/bug_repository_impl.dart

@@ -9,13 +9,6 @@ import 'package:dpip/features/bug_tracker/domain/bug_thread.dart';
 import 'package:dpip/features/bug_tracker/domain/bug_repository.dart';
 import 'package:flutter/foundation.dart';
 
-/// The forum tag that marks a thread as about THIS app. A routing marker, not
-/// a category — it is filtered on and never rendered.
-///
-/// In canonical form: see [canonicalBugTag] for why the two endpoints disagree
-/// about how they spell it.
-const String appBugTag = 'dpip';
-
 class BugRepositoryImpl implements BugRepository {
   const BugRepositoryImpl(this._api);
 
@@ -44,22 +37,20 @@ String _normalise(String body) => body.replaceAllMapped(
   (match) => match.group(1) ?? match.input,
 );
 
-/// The two tracker endpoints spell the same tag two different ways.
+/// A tag as the app matches it: the forum's slug, lower-cased.
 ///
-/// The index sends the forum's slugs — `["dpip", "bug"]`. The detail endpoint
-/// still reflects Discord's raw forum labels, which are bilingual — `["臭蟲
-/// bug", "DPIP", "已解決 fixed"]`. Left alone, one thread carries `bug` in the
-/// list and `臭蟲` on its own page, and the routing marker matches `dpip` in
-/// one place and `DPIP` in the other — which drops every thread from the
-/// index, because nothing equals `DPIP` once the server started sending slugs.
+/// Both endpoints now send slugs — `["bug", "dpip", "fixed"]` — verified
+/// across the index and ten detail replies covering every tag in the
+/// vocabulary. They did not always agree: the detail endpoint used to reflect
+/// Discord's raw bilingual labels (`臭蟲 bug`, `DPIP`, `已解決 fixed`), so this
+/// took a label's English tail to reconcile the two. That split is gone with
+/// the behaviour it compensated for; a tag with a space in it is now a tag
+/// with a space in it.
 ///
-/// The slug is the canonical form, so a bilingual label yields its English
-/// tail. `臭蟲 bug` → `bug`, `DPIP` → `dpip`, `bug` → `bug`.
-String canonicalBugTag(String tag) {
-  final trimmed = tag.trim();
-  final space = trimmed.lastIndexOf(' ');
-  return (space < 0 ? trimmed : trimmed.substring(space + 1)).toLowerCase();
-}
+/// The lower-casing stays. It is what the routing marker actually needed —
+/// `DPIP` had to equal `dpip` or every thread fell out of the index — and it
+/// is one comparison against a regression whose other failure mode is silent.
+String canonicalBugTag(String tag) => tag.trim().toLowerCase();
 
 List<String> _canonicalTags(Object? raw) {
   if (raw is! List) return const [];
@@ -145,8 +136,11 @@ List<BugThread> parseBugThreads(Object? body) {
   ];
   // `dpip` is the forum's routing marker: threads without it are not about
   // this app (other products share the tracker), so they never reach the
-  // index. Locked threads are staff-side conversations — same. Matched in
-  // canonical form, because the marker arrives spelt both ways.
+  // index. `BugApi.list` already asks the server for that tag, so this is the
+  // backstop rather than the mechanism — a server that stops honouring the
+  // query would otherwise put another product's threads in this list with no
+  // other symptom. Locked threads are staff-side conversations, which the
+  // query cannot express at all.
   threads.removeWhere(
     (thread) =>
         thread.locked || !thread.tags.map(canonicalBugTag).contains(appBugTag),

test/features/bug_tracker/bug_repository_test.dart

@@ -2,10 +2,11 @@
 /// live tracker's updated contract (2026-08-27): a `users` directory keyed by
 /// Discord snowflake plus `threads`/`msg` entries that reference it by id.
 ///
-/// The two endpoints spell tags differently — the index sends the forum's
-/// slugs, the detail endpoint still reflects Discord's bilingual labels — so
-/// the fixtures deliberately use both forms and both must canonicalise the
-/// same way.
+/// Both endpoints send the forum's slugs, lower-case (`["bug", "dpip"]`). The
+/// detail endpoint used to reflect Discord's bilingual labels instead; the
+/// fixtures still put a upper-case marker through the parser, because that is
+/// the spelling whose failure is silent — a routing tag that stops matching
+/// empties the whole list rather than mislabelling one badge.
 library;
 
 import 'package:dpip/features/bug_tracker/data/bug_repository_impl.dart';
@@ -50,14 +51,14 @@ void main() {
     );
   });
 
-  test('the index accepts the detail endpoint\'s bilingual labels too', () {
+  test('a tag is matched by its slug, whatever case it arrives in', () {
     final threads = parseBugThreads({
       'users': {_chenId: _user(_chenId, '陳')},
       'threads': [
         {
           'threads_id': 1,
           'title': 't',
-          'tags': ['DPIP', '臭蟲 bug', '已解決 fixed'],
+          'tags': ['DPIP', 'Bug', 'fixed'],
           'body': 'b',
           'author': _chenId,
           'created_at': 1787511150,
@@ -66,8 +67,9 @@ void main() {
       ],
     });
 
-    // Canonical form is the slug, so the English tail wins and the routing
-    // marker matches whichever way the server spelt it.
+    // The marker matched despite its case (the thread survived at all), and
+    // the categories come through lower-cased, which is the form the badge
+    // table is keyed by.
     expect(threads.single.tags, ['bug', 'fixed']);
   });