* fix: fix and improve test isolation and collision with environment
* docs: remove unnecessary comment
* test(env-isolation): clear CODEBURN_FORCE_MACOS_MAJOR and pin TZ
Two env vars read in src/ were not isolated: CODEBURN_FORCE_MACOS_MAJOR
(now cleared so it cannot leak between tests) and TZ (now pinned to UTC,
since clearing it falls back to the OS zone and would shift date buckets
versus a clean CI runner).
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Co-authored-by: AgentSeal <hello@agentseal.org>
Large Cursor DBs were scanned as "the most-recent 250k bubbles by ROWID",
which dropped in-range older sessions from long-range reports and warned even
when the requested window fit comfortably. The bubble timestamp lives in the
JSON value (no index), so the date filter forces a full decode per row, which
is why a scan bound exists.
Replace the blind cap with a range-aware paged scan: for DBs over the budget,
page ROWID-descending, keep only rows within the window (createdAt > timeFloor),
and stop once a full page falls past the window floor. The hard budget remains
as a backstop for genuinely enormous in-range scans, and the "older sessions
may be missing" warning now fires only when that budget is actually hit.
Effect: short ranges decode far fewer rows and no longer warn; long ranges
return the full window when it fits the budget; truncation keeps the newest
in-range bubbles and warns only then. Small DBs are unchanged (un-paged query).
Budget is overridable via CODEBURN_CURSOR_MAX_BUBBLES for tests.
