* fix: derive leaf from fossil's branch rule and bound the deferral rollup

Leaf derivation dropped 66% of rows on the real Fossil repository (487 of 1,426) because both leaf paths treated any parent link as retiring a leaf. Canonical fossil retires a check-in only when a child carries the *same* branch name, with an absent branch tag reading as "trunk" (src/leaf.c: is_a_leaf / leaf_check / leaf_rebuild all share that predicate and none consult plink.isprim). Verified against fossil 2.28 itself: after a branch commit off the trunk tip, both the incremental table and `fossil rebuild` keep the trunk tip as a leaf even though its only child is its primary child, and a branch tip merged into trunk stays a leaf as well.

Two code paths were wrong, in the same way:

- repairLeafTable excluded every `pid` in plink, so merged branch tips disappeared -- the class that accounts for 939 of the corpus's leaves. - Checkin deleted every parent from leaf, so committing onto a new branch silently retired the branch point.

Both now share leafCheck/repairLeafTable in internal/manifest/leaf.go. The recompute also has to run after tag propagation rather than before it: a check-in that declares no branch of its own only has a branch value once propagation has written it, and comparing against a missing value made every inherited-branch tip look like a leaf.

Applying the new predicate to the real repository's own event/plink/tagxref yields 1,428 against fossil's 1,426, and every one of the six differing rows is fossil's incremental bookkeeping rather than its predicate: 2 are phantom rids fossil's leaf_check inserts as plink parents of check-ins it linked, and 4 are parentless check-ins with no branch tag, which nothing ever enqueues for a leaf check. Running fossil's own leaf_rebuild() on that repository gives 1,494, so it is leaf_check, not leaf_rebuild, that the shipped table reflects.

Also caps the deferral rollup's identifier lists (issue #194). A clone deferring 180 check-ins on 417 missing blobs rendered a single ~28 KB log line; the counts stay exact at INFO and the lists print eight entries plus an "...and N more" so nothing is dropped without saying so.

Fixes #189 Fixes #194

* chore: retrigger code scanning after branch restore check-in: df495ba69e user: [email protected] tags: trunk