Add subreddit tone profiles for message style guidance

Introduces a tone-profile system that lets the processor adapt outgoing
message style per-subreddit (and per-flair) instead of using one tone
for everything. Profiles act as a "tone mic" layered after the base
prompt and strategy override, so they shape voice without redefining
the whole message.

- src/config/tone-profiles.ts defines the catalog (default, dominant,
  submissive, playful, direct, ...) and a resolveTone() helper that
  falls back to the default profile for unknown keys.
- config.yaml maps subreddits to tone keys; the schema in
  src/config/index.ts validates it.
- src/services/processor.ts threads the resolved tone into the prompt
  build, picking based on subreddit and optional link flair.
- src/reddit/api.ts adds link_flair_text to RedditPost so the
  processor can use it for tone selection.
- src/ai/openrouter.ts accepts and forwards the tone-shaped prompt.
- public/index.html surfaces the active tone in the dashboard.
- Tests cover the catalog, config validation, and processor integration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/reddit/api.ts

@@ -24,6 +24,7 @@ export interface RedditPost {
   created_utc: number;
   over_18: boolean;
   spoiler: boolean;
+  link_flair_text?: string | null;
 }
 
 // Extracts URL-ish tokens (with or without scheme) and returns the first