For those following my little Civic saga:

the problem turned out to be a spring popping out of the clutch disc. Another
spring was about to go and the release bearing was noisy so it was about due
for a clutch replacement anyway. i'm a bit envious of those who got a few more
years and few more 10k miles out of their original clutch.

the clutch master cylinder is working fine even though it's leaking a bit
around the seal.

it's shifting like butter now...hallelujah brother!