feat: PDF Viewer translation via context menu and two-mode Action Popupv0.1.0

Add Firefox built-in PDF Viewer support using only public WebExtensions
APIs: a selection context menu ("選択したテキストを翻訳") starts a
translation and the toolbar Action Popup shows the streaming result.
No content-script injection into the privileged PDF Viewer, no PDF.js
internals, no separate windows, no custom viewer (Specifications.md §4.6).

Specification alignment (Phase 1)
- Specifications.md: new requirements PDF-01..04 (PDF selection
  translation), CTX-01..03 (context menu translation), POP-01..06
  (popup two modes); SEL-06 updated to route PDF through the menus API;
  section 13.4 adds a 14-item manual PDF verification checklist; section
  15 removes "Firefox内蔵PDF Viewerへの対応" from out-of-scope
- Design.md: architecture diagram with the menus path, menu-translation
  component, menus permission, popup translation-result state machine
  (idle/starting/streaming/completed/error/cancelled), shared translation
  state (§9.2), context-menu integration phase, test plan and API audit
  checklist items (menus permission scope, no PDF Viewer internals)
- Security.md: menus permission restricted to selection-context
  translation; PDF Viewer treated as privileged browser UI (no injection,
  no wrappedJSObject/cloneInto/exportFunction, no internal DOM access);
  menus.OnClickData.selectionText treated as untrusted input passing the
  same validation pipeline; popup result rendering stays textContent-only

Background (Phase 2)
- translation-service.js (new): the single translation pipeline shared by
  every entry point - selection validation (type/trim/empty/control
  chars/max length), prompt building, Ollama request, session/abort, and
  the shared translation state (requestId, sourceText, translatedText,
  status, model, error, startedAt, source). "source" is metadata only; a
  PDF-specific translation engine does not exist
- menu-translation.js (new): validates menus.OnClickData.selectionText
  and starts a sink-less translation observed via GET_POPUP_STATE
- message-router.js: routes port translations through the shared service;
  new runtime messages GET_POPUP_STATE and REGENERATE_LAST; popup-state
  port handler broadcasts live state (initial push + every chunk/status
  change) so an open popup shows streaming progress in real time
- index.js: registers the selection context menu (contexts: ["selection"]
  only, no menus.onShown) and calls browser.action.openPopup()
  synchronously inside the click user gesture, catching failures so a
  popup-open problem never breaks the translation itself
- manifest.json: permissions now ["storage", "menus"]
- settings-service.js: __resetCacheForTests hook for test isolation

Popup two-mode UI (Phase 3)
- popup.html/js/css: mode nav (設定 / 翻訳). Translation mode shows
  status, model, streaming text (textContent only), user-safe error, and
  copy (Clipboard API only, no execCommand fallback), regenerate (new
  requestId reusing the stored source text) and a settings shortcut.
  Closing the popup never cancels the request; reopening shows the
  latest text and continues receiving chunks live. Initial mode: active
  (starting/streaming) translation wins, otherwise the last tab the user
  picked is restored (storage.local.popupMode, default settings)

Fresh-install model auto-selection
- translation-service.js ensureModelConfigured(): when storage.model is
  empty, pick the first model from the running Ollama and persist it
  before translating, mirroring the popup/options auto-select. A user who
  never opened any settings UI can translate immediately; when Ollama is
  unreachable a clear OLLAMA_UNAVAILABLE message is shown

User-safe error details
- detailForUser(): strips URLs (no internal host names echoed to the UI),
  caps length at 120 chars, drops full JSON response bodies, and hides
  meaningless low-level network errors so the popover/popup shows the
  base message plus at most a short, safe detail

Tests: 85 passed, 0 failed
- selectionText validation (untrusted input pipeline)
- menu selection -> translation -> popup state streaming/completed
- empty selection rejected without starting a request
- streaming status transitions observed through GET_POPUP_STATE
- Ollama unreachable surfaces a user-safe error into popup state
- newer request replaces older state (abort semantics)
- regenerateLast reuses source text with a fresh requestId
- popup-state port receives live broadcasts; wrong port names ignored
- fresh-install auto-select persists the first Ollama model
- error detail sanitization (URL stripping, length cap, JSON drop)
- popup/options smoke tests updated for the two-mode markup
- setupRouter resets the shared settings cache for test isolation

Docs: README documents the two-mode popup and PDF flow; Testing-Results
records automated results and the manual PDF checklist (to be executed).

No git-side surprises: this commit was created explicitly on request
(requirement 18 of the PDF task had deferred commits until now).

1 files changed, 26 insertions, 1 deletions

diff --git a/doc/Testing-Results.md b/doc/Testing-Results.md
index b2cf153..a9abf8a 100644
--- a/doc/Testing-Results.md
+++ b/doc/Testing-Results.md
@@ -6,7 +6,7 @@
 
 実行環境: Firefox系ブラウザ（Geckoエンジン）で `tests/test.html` を実行。npm / Node.js 不使用の自作ランナー。
 
-**結果: 71 passed, 0 failed**
+**結果: 85 passed, 0 failed**
 
 ### カバレッジ
 
@@ -28,6 +28,10 @@
 | toExtensionError | 2 | AbortError→REQUEST_ABORTED、デフォルトコード |
 | TranslationSession | 2 | 新規要求で旧要求Abort+旧portへの通知、isActive/clear |
 | settings service | 3 | 保存/復元ラウンドトリップ、不正値フォールバック、onChangedキャッシュ更新 |
+| selectionText validation | 1 | **context menu選択文字列のuntrusted validation**（型/trim/空/control文字/最大長） |
+| context menu flow + popup state | 11 | **menus選択→翻訳→popup state streaming/completed**、空選択拒否、streaming状態遷移、Ollama停止時error、新規翻訳で旧state置換、regenerateLast、**popup-state portライブ配信**、誤名port拒否、**初期状態のモデル自動選択（未設定→先頭モデルを自動永続化）**、Ollama停止時のOLLAMA_UNAVAILABLE報告、エラー詳細のユーザー安全化（URL除去・長さ制限・JSON除去） |
+| UI smoke (popup) | 1 | popup.js実DOM実行、2モードUI初期化、settings mode初期表示 |
+| UI smoke (options) | 1 | options.js実DOM実行、言語/モデル/host反映 |
 | message router: port flow | 5 | started/chunk/completed伝送、**A→B新規要求でAがabort+stale chunk廃棄**、不正メッセージ破棄、OLLAMA_UNAVAILABLE、INVALID_SETTINGS |
 | message router: listModels | 2 | 正常系、非信頼sender拒否 |
 
@@ -52,6 +56,27 @@
 | 13 | ページ内のHTMLらしき文字列やscript文字列を選択してもDOM実行されない | ☐ 未実施 |
 | 14 | LLM出力にHTML文字列が含まれてもHTMLとして解釈されない | ☐ 未実施 |
 
+## 2.1 PDF Viewer実機動作確認（context menu翻訳）
+
+以下はSpecifications.md §13.4の14項目です。実Firefox + 実Ollamaで確認してください。
+
+| # | 確認項目 | 結果 |
+|---|---|---|
+| 1 | 通常Webページで文字列を選択する | ☐ 未実施 |
+| 2 | context menuに「選択したテキストを翻訳」が表示される | ☐ 未実施 |
+| 3 | menuからtranslationを開始できる | ☐ 未実施 |
+| 4 | Firefox内蔵PDF ViewerでPDFを開く | ☐ 未実施 |
+| 5 | PDF内のテキストを選択する | ☐ 未実施 |
+| 6 | context menuに翻訳項目が表示される | ☐ 未実施 |
+| 7 | `selectionText` が取得される | ☐ 未実施 |
+| 8 | Action Popupが開く | ☐ 未実施 |
+| 9 | Ollama streaming結果が逐次表示される | ☐ 未実施 |
+| 10 | Copyが動く | ☐ 未実施 |
+| 11 | Regenerateが動く | ☐ 未実施 |
+| 12 | Ollama停止時に安全なエラー表示になる | ☐ 未実施 |
+| 13 | HTML/script風のPDF文字列を選択しても実行されない | ☐ 未実施 |
+| 14 | 新しい翻訳開始時に古いrequestが正しくcancelされる | ☐ 未実施 |
+
 ## 3. セキュリティチェック
 
 | 項目 | 結果 |