feat: Firefox selection translation extension with local Ollama (initial version)

Implement the complete initial version of a Firefox WebExtension (Manifest V3)
that translates selected text on web pages using a local Ollama LLM and shows
the result in a small popover near the selection.

Specification alignment (Phase 0)
- Unified Specifications.md / Design.md / Security.md on the same approach:
  Ollama REST API + Fetch API + NDJSON streaming (no ollama-js SDK dependency)
- Fixed host_permissions to http://localhost/* and http://127.0.0.1/* because
  Firefox match patterns do not support port numbers (bug 1362809/1468162);
  the actual connection target is restricted to localhost/127.0.0.1 + any port
  by application-side validation (defense in depth, OLL-09)
- Clipboard: use navigator.clipboard.writeText() only inside the copy button
  click (user activation); no deprecated execCommand fallback

Implementation (zero dependencies, vanilla JS, no npm/Node required)
- manifest.json: MV3, background.scripts + type:module (event page, no
  service_worker), action popup, options_ui, content_scripts for http/https,
  permissions: storage + localhost host permissions only
- src/shared: constants (ports, limits, presets, error codes), message
  validation, settings schema (defaults / merge / sanitize / buildOptions /
  toApiThinking), system prompt builder (fixed prompt first + user prompt)
- src/background: message-router (runtime.Port streaming + runtime.onMessage
  for model list), translation-session (single active request, abort previous
  on new request, stale chunk suppression), ollama-client (fetch against
  /api/tags and /api/chat with buffering NDJSON line parser tolerant to chunk
  boundaries inside JSON objects, AbortController, host re-validation before
  every request, HTTP status to error-code mapping), settings-service
  (storage.local load/save with validation and fallback to defaults)
- src/content/content.js: single classic script (Firefox does not support ES
  modules in content scripts) with selection detection (selectionchange +
  mouseup + keyup, debounced), Shadow DOM action button, Shadow DOM popover
  with HIDDEN/LOADING/STREAMING/COMPLETED/ERROR state machine, port client
  with requestId-based stale chunk filtering, enabled-state sync via
  storage.onChanged; all dynamic text rendered via textContent only
- src/popup + src/options: full settings UI (enable toggle, Ollama host,
  model list from Ollama with saved-model warning, target language, thinking
  mode, temperature slider 0.0-2.0 step 0.1, context length presets
  4k/8k/16k/32k/128k/256k, seed random/fixed with integer value, user system
  prompt, advanced numeric options with steppers, stop sequences textarea)
- icons generated by tools/make-icons.ps1 (System.Drawing, no external tools)
- build.ps1 packages manifest.json + icons/ + src/ into dist zip, excluding
  tests/, doc/, ollama-js/ and tools/

Tests (71 passed, 0 failed)
- In-browser test runner (tests/test.html) with custom describe/it/assert
  framework; no npm, no Node.js
- Unit: constants sync between content mirror and shared module, Ollama host
  validation (localhost/127.0.0.1 + any port only; rejects external hosts,
  LAN IPs, https, credentials, paths), settings schema defaults and fallback,
  temperature 0.1-step validation, context length presets, seed modes,
  advanced option types, buildOptions omission of unset values and absence of
  tfs_z/mirostat fields, system prompt composition order, message validation
  with selection length boundary values
- Integration: NDJSON streaming across awkward byte boundaries, thinking
  chunk forwarding, malformed line tolerance, error payload mapping, think/
  options inclusion rules, model list, TranslationSession abort semantics,
  settings round-trip with storage.onChanged cache refresh, full port flow
  (started/chunk/completed), newer request aborts older with stale chunk
  discard, malformed message rejection, OLLAMA_UNAVAILABLE and
  INVALID_SETTINGS error paths, untrusted sender rejection

Security audit (Design.md section 24 checklist: all pass)
- No innerHTML/outerHTML/document.write/eval/new Function/localStorage
- No remote JS/CSS/fonts/CDN resources; no inline scripts in extension pages
- Ollama access limited to background; content scripts never fetch Ollama
- Background validates message type/length/requestId; single concurrent
  translation enforced
- Clipboard API only (no execCommand fallback)
- Minimal permissions: storage + localhost host permissions

Docs
- README.md with build/load/usage instructions, API list, permission rationale
- doc/Testing-Results.md with automated test results, security audit results,
  and a 14-item manual Firefox verification checklist (to be executed on a
  real Firefox + Ollama environment)

1 files changed, 143 insertions, 0 deletions

diff --git a/src/options/options.css b/src/options/options.css
new file mode 100644
index 0000000..7de8418
--- /dev/null
+++ b/src/options/options.css
@@ -0,0 +1,143 @@
+body {
+  margin: 0;
+  padding: 24px;
+  font-family: system-ui, sans-serif;
+  font-size: 14px;
+  color: #1f1f1f;
+  background: #fafafa;
+}
+
+main {
+  max-width: 640px;
+  margin: 0 auto;
+  background: #ffffff;
+  border: 1px solid rgba(0, 0, 0, 0.12);
+  border-radius: 8px;
+  padding: 20px 24px;
+}
+
+h1 {
+  font-size: 18px;
+  margin: 0 0 16px;
+}
+
+fieldset {
+  border: 1px solid rgba(0, 0, 0, 0.15);
+  border-radius: 6px;
+  margin: 0 0 16px;
+  padding: 12px 16px;
+}
+
+legend {
+  font-weight: 600;
+  padding: 0 6px;
+}
+
+.field {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+  margin-bottom: 14px;
+}
+
+.field.inline {
+  flex-direction: row;
+  align-items: center;
+  gap: 8px;
+}
+
+label,
+.label-text {
+  font-weight: 500;
+}
+
+.hint {
+  color: #5f6368;
+  font-size: 11px;
+  margin: 2px 0 0;
+}
+
+.status {
+  color: #5f6368;
+  font-size: 12px;
+}
+
+.status.error {
+  color: #c5221f;
+}
+
+input[type='text'],
+input[type='number'],
+select,
+textarea {
+  font-family: system-ui, sans-serif;
+  font-size: 13px;
+  padding: 4px 6px;
+  border: 1px solid rgba(0, 0, 0, 0.25);
+  border-radius: 4px;
+}
+
+textarea {
+  resize: vertical;
+}
+
+.inline {
+  display: flex;
+  gap: 6px;
+  align-items: center;
+}
+
+.inline select {
+  flex: 1;
+  min-width: 0;
+}
+
+.inline input[type='number'] {
+  width: 120px;
+}
+
+.segmented {
+  display: flex;
+  gap: 12px;
+  margin: 4px 0;
+}
+
+.segmented label {
+  font-weight: 400;
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+#seed-value-row {
+  margin-top: 4px;
+}
+
+.actions {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+#save {
+  padding: 6px 24px;
+  border: 1px solid rgba(0, 0, 0, 0.25);
+  border-radius: 4px;
+  background: #1a73e8;
+  color: #fff;
+  cursor: pointer;
+  font-size: 13px;
+}
+
+#save:hover {
+  background: #1765cc;
+}
+
+.dev-link {
+  margin-top: 16px;
+  font-size: 11px;
+}
+
+.dev-link a {
+  color: #5f6368;
+}
\ No newline at end of file