v0.5.2 — jargon lists, a scoped-write fix, and a CI gate

Covers everything since v0.4.2 (0.4.3, 0.5.0 and 0.5.1 were never released on their own).

What's new

• User jargon lists: Rule 18 and /iceberg:jargon (#8). Pick an industry pack, name your own words, or both; /iceberg:edit and /iceberg:score apply the list automatically once .iceberg/jargon.txt exists.
• Write access is scoped (#10, #11). edit no longer pre-approves Write (it asks before overwriting your file), and score, jargon and the score agent are limited to ./.iceberg/**. This clears the upload scanner's unscoped-write finding.
• A CI gate on every PR (#10, #12). It fails on unscoped Write/Edit/Bash grants, whole-environment reads in shipped code and committed executables, and runs claude plugin validate --strict.
• Directory icon (#9) and a README that discloses the Stop hook (#7).

No binaries: iceberg is skills and agents only, so there is nothing to attach to this release.