v0.6.15

Hotfix surfaced by the tokenomics agent's v0.6.14 verification cycle.

Fixed — post-merge hook skips regen on default branch

After gh pr merge --squash --delete-branch, the post-merge hook fires on main. v0.6.14 correctly fixed the orphan-branch-blocks-checkout failure (issue #112), but on main the regen still ran — producing output that DIFFERED from origin/main (the squash compressed history that the local regen reads), leaving docs/timeline.md + docs/file-structure.md as unstaged modifications on every merge cycle. Every merge needed a manual git checkout -- docs/timeline.md docs/file-structure.md to make local main clean.

v0.6.15: the hook now exits 0 when the current branch matches refs/remotes/origin/HEAD's symbolic ref (the default branch). The regen-timeline.yml workflow already handles main server-side; local main converges on next pull. Trade "immediate local view of the new entry" for "main matches origin/main after every merge" — the latter is what users expect.

Trade-off accepted (alternatives considered + rejected):

• Pre-merge regen via a server-side workflow committing to PR branch → invasive (extra commit per PR, requires PAT, adds CI time); deferred to a possible v0.7.x design
• Auto-amend the merge commit on main locally → surprising; would rewrite history mid-pull
• Document git checkout -- docs/ as the recommended cleanup → doesn't actually solve the "main should match origin/main" intent

Files: src/logmind/core/gitattributes.py _build_post_merge_hook_body extends the orphan-branch guard with a default-branch guard; tests/test_merge_driver.py adds test_post_merge_hook_body_embeds_default_branch_skip_logic.

Validation gate

• pytest -q green: 829 passed, 1 skipped (+3 over v0.6.14).
• After v0.6.15 propagates + tokenomics agent re-upgrades: next gh pr merge --squash --delete-branch should leave git status clean on main (no unstaged docs files). Verifies the structural fix end-to-end.