docs: the privacy claim gets stronger, so the documents have to say so

Removing BetterTTV took out the plugin's only outbound network call, and five
documents were still describing it as present. PRIVACY.md led with "one outbound
network call exists by design" -- the opposite of what shipped an hour ago, and
the one claim in that file people actually check.

PRIVACY.md now opens with none at all. The section that described the call is
kept and marked as removed rather than deleted, so the claim can be read against
what it replaced: the startup fetch meant BetterTTV saw an IP as soon as the
plugin loaded, whether an emote ever appeared or not. Worth leaving visible.
BetterTTV also comes out of the third-party table, which now lists only the two
parties nobody using this plugin through Dalamud can avoid.

SECURITY.md listed the EmoteCache HTTP client as in scope for reports. There is
nothing there to report on.

THIRD_PARTY_NOTICES.md named the call as current; both entries it has ever
carried are now historical.

README dropped the pointer to the outbound call and the switch for it, a
stability bullet about a crash fix in code that no longer exists, and the line in
the Chat 2 migration that moved an emote cache directory nothing reads.

ROADMAP gained 2.0.1 and 2.0.2, and a section for what the 2.0.0 push left
behind: 47 overlong comment blocks, channel names translated in only ten of the
25 languages, an orphaned EmoteCacheV1 directory on anyone who ran an older
build, and the deprecated GlobalScaleSafe call that is the last compiler warning
in the build.

SECURITY.md

@@ -24,7 +24,6 @@ I respond on weekdays during European business hours.
   influence)
 - The privacy filter in `MessageStore.cs` and the export pipeline
 - The configuration migration logic
-- The `EmoteCache` HTTP client and path handling
 - The Auto-Tell-Tabs spawn logic and history preload
 
 ### Out of scope