Rebalance author reputation weights — prioritize X/Twitter signals

[realproject7]

Problem

The author reputation weights in the trending algorithm (PR #582) don't reflect PlotLink's target audience. PlotLink wants to attract X/Twitter users, not just Farcaster users. The current weights over-index on Neynar/Quotient scores which are Farcaster-centric.

Current weights (wrong)

Signal	Current Weight
FC followers	25%
X followers	20%
X verified	10%
Neynar score	25%
Quotient score	20%

New weights

Signal	New Weight
FC followers	25%
X followers	60%
X verified	5%
Neynar score	5%
Quotient score	5%

Fix

In lib/ranking.ts, update the computeAuthorReputation() return statement:

return (
  fcSignal * 0.25 +
  xSignal * 0.60 +
  verifiedSignal * 0.05 +
  neynarSignal * 0.05 +
  quotientSignal * 0.05
);

Branch

task/587-reputation-weights

Acceptance criteria

• Weights updated to FC 25%, X 60%, verified 5%, Neynar 5%, Quotient 5%
• Sum = 1.0
• Build passes