v0.415.2 — THE TAG-CHAIN SHIP (ALL-CONTEXTS-FIXED)

Guard v9's second blindspot, found by the timing: the v0.415.1 release run
failed FASTER (1m04s) than the green CI (1m29s) on the identical commit -
the gate itself was red in the release context only. Cause: actions/checkout
on a TAG push fetches exactly one tag (the one being built), so git tag -l
was non-empty and the zero-tags skip never fired; branch CI has zero tags
and skipped cleanly, which is why CI was green while the release was red.

- SHIP GUARD v9 final form: enforce ONLY where full tag history exists.
  Skip when GITHUB_ACTIONS is set or fewer than 100 tags are visible
  (the real chain is 400+). Teeth unchanged on Daniel's checkout, where
  the v0.413.0 failure class must be caught.
- Verified in FOUR contexts before this prep: repo checkout (enforcing,
  green), simulated branch-CI (0 tags, skip), simulated tag-CI (1 tag,
  skip), installed wheel (no .git, skip).
- v0.415.0 and v0.415.1: tagged, never published, superseded. Tag chain
  continuous - no new authorized gaps needed.
- Lesson: enumerate the contexts BEFORE shipping a context-sensitive
  guard. Branch CI, tag CI, dev checkout, installed layout are four
  different worlds.

Band content unchanged from v0.415.0: SHIP GUARD v9 tag-chain continuity,
hardened ship.ps1, honest v0.413.0 history. Physics untouched.
2,255 wired. Registry 6,820 rows. Gate 6,046/0. Acceptance 89/89.
