fix(guide): word each rule's one-liner no stronger than its confidence

Four legend epithets claimed more than their rules establish:

- rendered-not-emitted (medium): "so it is dead code". The rule sees only the
  scanned code and suppresses owners whose helper-method emissions it cannot
  resolve; it now says the branch is probably unreachable.
- riverpod-async-gap: "a failure shows a blank or stale screen". It can; the
  rule downgrades `bool` guard providers to info precisely because it often
  does not.
- notifier-field-unread (medium): "can never affect what the user sees". The
  check is a by-name read search in the scanned code; the finding message and
  the epithet now say "likely".
- provider-created-in-build: "on every rebuild and state is lost". The rule is
  info because rebuild frequency is unknown; it now says "if the widget
  rebuilds".

The README rules table and the rendered-not-emitted and notifier-field-unread
messages are aligned with the same wording.

README.md

@@ -148,7 +148,7 @@ Baselines and reports are JSON, so they diff and review like any other file.
 | Rule | What it means | Verified precision (with n) |
 | --- | --- | --- |
 | `emitted-not-rendered` | A state the bloc emits that no UI code matches, so the user never sees it. | **79/79 (100%)** factual on a CLEAN nuwayze main via an independent adjudicator with passing controls (`tool/adjudicate.py`). Reported once per **root cause**, not once per variant: one finding per unobserved union (dormant feature) and one per marker class when the union is observed. When the UI reads the union's payload through **base-class fields** the finding drops to info, because the data does reach the user. On clean nuwayze main: 30 findings covering 79 variant-level claims. |
-| `rendered-not-emitted` | A UI branch no state can reach: dead UI. | n=0 on nuwayze (unions whose bloc emits through helper methods are suppressed with a reason). Fires on a fixture with a passing negative control. |
+| `rendered-not-emitted` | A UI branch for a variant its bloc never emits in the scanned code: probably dead UI. | n=0 on nuwayze (unions whose bloc emits through helper methods are suppressed with a reason). Fires on a fixture with a passing negative control. |
 | `loading-not-reset` | An in-flight state whose failure path never resolves, so the spinner sticks. | n=0 on both dogfood repos, both verified to guard correctly; proven able to fire by fixture. |
 | `loading-flag-not-reset` | The same consequence for `copyWith` + `bool loading` state, which has no variant to match on. | **7/7 (100%)** on dex after hand adjudication; 4 characterised false positives were eliminated by the current gate. n=0 on nuwayze, verified correct. |
 | `event-without-handler` | A dispatched event with no `on<Event>`, so the interaction does nothing. | n=0 across the corpus; verified non-vacuous (168 dispatch sites on nuwayze all map to a registered handler). |
@@ -157,8 +157,8 @@ Baselines and reports are JSON, so they diff and review like any other file.
 | `notifier-never-notifies` | A `ChangeNotifier` method that changes observable state without ever notifying listeners. | Fixture contract only: **zero true positives** on the corpus (nuwayze 30 observable mutators, word_alive 36 — all of which notify). Gated on observable fields with lifecycle hooks excluded, after the first run was 9/9 false positives. |
 | `notifier-inert-consumer` | A notifier consumed by a `Consumer`/`Selector` with no notifying path at all, so those consumers can never rebuild. | Fixture contract only; no real-code true positives yet. |
 | `provider-read-in-build` | A `Listenable` read with `context.read` / `Provider.of(listen: false)` **directly in a build body**, so the widget never subscribes and can render stale state. | 1 finding on nuwayze from **447** raw `context.read` calls; 0 on word_alive/dex. Hand-verified: the first 4 findings were all reads inside **closures** (a `BlocListener` callback, a `Selector` builder), so a closure guard was added and only the direct-in-build case survives. |
-| `notifier-field-unread` | A public getter on a consumed `ChangeNotifier` that nothing reads, so the state it exposes cannot affect what the user sees. | 3 on nuwayze (e.g. `UserProvider.isInitializing`, `AppLocaleProvider.preferredLocale`), 0 on word_alive/dex. Reported once per notifier, and only for notifiers the UI actually consumes. **medium** confidence: a name match elsewhere can mask a genuinely unread member. |
-| `provider-created-in-build` | A provider constructed inside `build` without `.value`, so `create` reruns on every rebuild and state is lost. | 1 finding on nuwayze — `AppProviders.build` constructs **45** providers — from 45 raw sites, because it is reported **once per build method**. Deliberately **info**, not warning: the claim is factual, but a root `StatelessWidget` rarely rebuilds, so impact depends on rebuild frequency. |
+| `notifier-field-unread` | A public getter on a consumed `ChangeNotifier` that nothing reads, so the state it exposes likely never reaches the UI. | 3 on nuwayze (e.g. `UserProvider.isInitializing`, `AppLocaleProvider.preferredLocale`), 0 on word_alive/dex. Reported once per notifier, and only for notifiers the UI actually consumes. **medium** confidence: a name match elsewhere can mask a genuinely unread member. |
+| `provider-created-in-build` | A provider constructed inside `build` without `.value`, so if the widget rebuilds, `create` reruns and its state is lost. | 1 finding on nuwayze — `AppProviders.build` constructs **45** providers — from 45 raw sites, because it is reported **once per build method**. Deliberately **info**, not warning: the claim is factual, but a root `StatelessWidget` rarely rebuilds, so impact depends on rebuild frequency. |
 
 ### How precision was measured
 

lib/src/guide.dart

@@ -33,7 +33,8 @@ const Map<String, String> ruleEpithet = {
   ruleEmittedNotRendered:
       'A state the bloc emits that no UI code matches, so the user never sees it.',
   ruleRenderedNotEmitted:
-      'A UI branch that no state can reach, so it is dead code.',
+      'A UI branch for a variant its bloc never emits in the scanned code, so '
+      'the branch is probably unreachable.',
   ruleLoadingNotReset:
       'A loading state whose failure path never resolves, so the spinner sticks.',
   ruleLoadingFlagNotReset:
@@ -44,7 +45,8 @@ const Map<String, String> ruleEpithet = {
   ruleDeadHandler: 'An `on<Event>` registration that nothing ever dispatches.',
   ruleRiverpodAsyncGap:
       'An async Riverpod provider read in the UI whose error and/or loading '
-      'state is never rendered, so a failure shows a blank or stale screen.',
+      'state is never rendered, so a failure can leave a blank or stale screen '
+      'with no sign that anything went wrong.',
   ruleNotifierNeverNotifies:
       'A ChangeNotifier method that changes state without ever notifying '
       'listeners, so the UI keeps showing the old values.',
@@ -55,11 +57,11 @@ const Map<String, String> ruleEpithet = {
       'A Listenable read with `context.read` / `Provider.of(listen: false)` '
       'inside build, so the widget never subscribes and can go stale.',
   ruleNotifierFieldUnread:
-      'A public getter on a consumed ChangeNotifier that nothing reads, so the '
-      'state it exposes can never affect what the user sees.',
+      'A public getter on a consumed ChangeNotifier that nothing in the scanned '
+      'code reads by name, so the state it exposes likely never reaches the UI.',
   ruleProviderCreatedInBuild:
-      'A provider constructed inside build without `.value`, so a new instance '
-      'and listener are created on every rebuild and state is lost.',
+      'A provider constructed inside build without `.value`, so if the widget '
+      'rebuilds, a new instance and listener are created and its state is lost.',
 };
 
 /// Fixes that read the same under either policy.

lib/src/provider_rules.dart

@@ -821,8 +821,9 @@ String runProviderRules({
           confidence: 'medium',
           message:
               '${notifier.name} is consumed in the UI but ${unread.length} of '
-              'its public member(s) are read nowhere outside the class, so '
-              'nothing the user sees can depend on them: ${unread.join(', ')}.',
+              'its public member(s) are read by name nowhere outside the class '
+              'in the scanned code, so what the user sees likely does not depend '
+              'on them: ${unread.join(', ')}.',
           file: notifier.file,
           line: notifier.line,
           evidence: [

lib/src/rules.dart

@@ -609,7 +609,8 @@ FindingReport runChecks({
             confidence: 'medium',
             message:
                 '$variant is matched in UI code but ${coverage.union.owner} '
-                'never emits it, so that branch is dead.',
+                'never emits it in the scanned code, so that branch is probably '
+                'unreachable.',
             file: sites.isEmpty ? null : sites.first.path,
             line: sites.isEmpty ? null : sites.first.line,
             evidence: [