v1.14.2 — matcher precision: feed-label segment gate + short-alias word boundaries

Fixes #129. Two loose-match defects that attached a channel or stream carrying a different fixture.

• A team abbreviation in a provider's feed label no longer pairs with an opponent from the matchup body. USA Soccer07: Australia vs Turkey — the Australia-vs-Turkey feed — matched the Australia vs United States game, with USA supplied by the network label. Tier-1 channel names now require both sides in one :/| segment, the rule stream names have had since 1.8.0. Programme titles are deliberately not gated: XMLTV titles carry no feed labels.
• Short team aliases now match as whole tokens. As bare substrings the 2-4 character abbreviations were near-wildcards: NE hit Sportsnet and Tennessee, OM hit Roma, BOS hit Bosnia, GB hit GBN, PIT hit Jupiter, CLE hit Clearwater, Real hit Montreal. Longer keywords keep substring semantics.

The Diagnose action reports a channel name whose sides are split across label segments distinctly, instead of calling a correct rejection "unexpected".

Verified against a live 6588-channel / 16415-stream instance: replaying the real slate is unchanged, and a differential over the whole corpus across 33 fixtures drops exactly two Tier-1 matches, both false positives, and gains none. 3488 tests pass.

README gains a "How games are matched" section covering the three match paths and both precision rules.