review: clarify two-pass matched-skip and tighten modelComponentsMatch loop bound

Two low/medium review notes, both clarity (no behavior change):

• Two-pass session matching: the 'already matched' skip was already present (folded into the pass condition with ||). Split it into a standalone 'if matched[i] != nil { continue }' so it's unmistakable, and noted that matched stays index-aligned with summary.AgentRuns. Added a test: an explicit-model inspector with no matching session is left unlinked (not misattributed to the default session) while the default inspector still links.

• modelComponentsMatch: a legitimate match always needs a numeric component after the matched span, so the end-aligned window can never match. Tightened the loop bound from <= to < len(long) to make that strict-subspan invariant explicit in the loop, dropping the now-dead 'end < len(long)' body check. Existing model-match table tests still pass.