docs: switch Privacy Monitor default to XposedOrNot (free, keyless)

Email breach endpoints need no API key (2 req/s, cached), so Privacy Monitor
ships enabled by default. HIBP kept as a swappable key-based alternative;
provider chosen via Privacy:Provider config.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/specs/feature-privacy-monitor.md

@@ -1,10 +1,28 @@
 # Spec: Privacy Monitor (data-breach checking)
 
-Checks the user's email address (and optionally addresses they've corresponded with)
-against known data breaches. Spec'd around **Have I Been Pwned (HIBP)**, shipped behind
-a config flag that stays **off until an API key is provided** — zero cost until then.
+Checks the user's email address against known data breaches. **Default provider:
+[XposedOrNot](https://xposedornot.com/api_doc)** — free, no API key required for email
+endpoints. HIBP is kept as a swappable alternative behind a key. Because it's free and
+keyless, Privacy Monitor ships **enabled by default** (it only ever checks the
+signed-in user's own address).
 
-## 1. Configuration
+## 1. Provider details (XposedOrNot)
+
+No auth for email endpoints. Rate limit: **2 req/sec per IP** (we cache, so this is a
+non-issue). Two endpoints:
+
+| Purpose | Request | Returns |
+|---------|---------|---------|
+| Quick check | `GET https://api.xposedornot.com/v1/check-email/{email}` | `{ "breaches": [["Name1","Name2",…]], "email", "status":"success" }`; or `{ "Error":"Not found", "email":null }` when clean |
+| **Rich analytics** (what we use) | `GET https://api.xposedornot.com/v1/breach-analytics?email={email}` | `BreachesSummary`, **`ExposedBreaches`** (entity name, industry, risk level, exposed data types, year, record count), `BreachMetrics`, `ExposedPastes` |
+
+We call **`breach-analytics`** to populate the rich UI. A `404`/`Error:"Not found"`
+means "no breaches" → return empty, not an error. We call the REST API directly via a
+named `HttpClient` (consistent with the existing `ollama`/`openai`/`unsubscribe`
+clients); the official `XposedOrNot-DotNet` SDK exists but we avoid the extra dependency
++ audit surface.
+
+## 2. Configuration
 
 `PrivacyOptions` (new, `Configuration/Options.cs`):
 
@@ -12,21 +30,35 @@ a config flag that stays **off until an API key is provided** — zero cost unti
 public class PrivacyOptions
 {
     public const string SectionName = "Privacy";
-    public bool Enabled { get; set; } = false;     // master flag
-    public string Provider { get; set; } = "Hibp";  // "Hibp" | "None"
-    public string? HibpApiKey { get; set; }          // required for Hibp
-    public int CacheHours { get; set; } = 24;        // don't hammer the API
+    public bool Enabled { get; set; } = true;             // free + keyless → on by default
+    public string Provider { get; set; } = "XposedOrNot";  // "XposedOrNot" | "Hibp" | "None"
+    public string? HibpApiKey { get; set; }                // only needed if Provider="Hibp"
+    public int CacheHours { get; set; } = 24;              // don't re-check more than daily
 }
 ```
 
-`appsettings.json` gains a `Privacy` section with `Enabled: false`, empty key.
-`IsEnabled => Enabled && Provider == "Hibp" && !string.IsNullOrWhiteSpace(HibpApiKey)`.
-
-## 2. Provider abstraction
+`appsettings.json` gains a `Privacy` section: `Enabled: true`, `Provider:
+"XposedOrNot"`, empty `HibpApiKey`.
 
 ```csharp
-public record BreachDto(string Name, string Title, string Domain, DateOnly BreachDate,
-                        IReadOnlyList<string> DataClasses, bool IsVerified, string? Description);
+// XposedOrNot needs no key; Hibp does.
+IsEnabled => Enabled && Provider switch {
+    "XposedOrNot" => true,
+    "Hibp"        => !string.IsNullOrWhiteSpace(HibpApiKey),
+    _             => false
+};
+```
+
+> **Privacy note:** this sends the user's own email address to a third-party service.
+> That's the feature's purpose and it's the signed-in user's own address, but it stays
+> a single config flag away from off, and we never check anyone else's address.
+
+## 3. Provider abstraction
+
+```csharp
+public record BreachDto(string Name, string Title, string? Domain, int? Year,
+                        IReadOnlyList<string> DataClasses, string? RiskLevel,
+                        string? Industry, string? LogoUrl, string? Description);
 
 public interface IBreachProvider
 {
@@ -36,12 +68,20 @@ public interface IBreachProvider
 }
 ```
 
+- **`XposedOrNotBreachProvider`** (default) — `GET /v1/breach-analytics?email={url-encoded}`
+  on the `"xposedornot"` named client. Map `ExposedBreaches.breaches_details[]`
+  (`breach`, `xposed_data` → `DataClasses`, `xposed_date`/`year`, `industry`,
+  `risk` → `RiskLevel`, `logo`, `details` → `Description`) into `BreachDto`. Treat
+  `Error:"Not found"` / `404` as clean (empty). `429` → respect backoff, return
+  cached/empty. No key, no `user-agent` requirement.
 - `HibpBreachProvider` — `GET https://haveibeenpwned.com/api/v3/breachedaccount/{account}?truncateResponse=false`,
-  header `hibp-api-key`, a descriptive `user-agent`. Handle: `404` = no breaches (return
-  empty), `401` = misconfig (log, treat as disabled), `429` = rate-limited (respect
-  `Retry-After`, return cached/empty). Uses a named `HttpClient` "hibp" with a sane timeout.
-- `NullBreachProvider` — `IsEnabled => false`, returns empty. Registered when the flag is off
-  (mirrors the `NullAiProvider` pattern in `DependencyInjection`).
+  header `hibp-api-key`, descriptive `user-agent`. `404` = clean, `401` = misconfig (log,
+  disable), `429` = back off. Used only when `Provider="Hibp"` + key set.
+- `NullBreachProvider` — `IsEnabled => false`, returns empty. Registered when
+  `Provider="None"` or the chosen provider isn't usable (mirrors `NullAiProvider`).
+
+DI selects the provider by `PrivacyOptions.Provider` (switch in `DependencyInjection`,
+same shape as the AI provider selection).
 
 ## 3. Service
 
@@ -85,7 +125,9 @@ never arbitrary addresses (avoids turning the app into a breach-lookup tool for
 ## 6. Security & safety
 
 - [ ] Only the authenticated user's own address is ever checked (no lookup of others).
-- [ ] API key read from config/secrets, never logged, never sent to the client.
-- [ ] Feature fully inert (endpoints return `{ enabled:false }`, nav hidden) until a key is set.
-- [ ] Rate-limit/backoff respected; failures degrade to cached/empty, never crash.
-- [ ] HIBP responses cached to minimize external calls and avoid leaking usage patterns.
+- [ ] Any API key (HIBP path) read from config/secrets, never logged, never sent to the client.
+- [ ] Feature can be fully disabled via `Privacy:Enabled=false` or `Provider="None"`
+      (endpoints return `{ enabled:false }`, nav hidden).
+- [ ] Rate-limit/backoff respected (XposedOrNot 2 req/s); failures degrade to cached/empty, never crash.
+- [ ] Provider responses cached (`CacheHours`) to minimize external calls and avoid leaking usage patterns.
+- [ ] Email is URL-encoded into the request path/query; no other PII is sent.